Mopar 340 j heads They were the Mopar Performance version of the '90s '308' head. Casting #3671587, listed for 1973 340. Aug 3, 2023 · This is the cylinder head used on the Mopar 440 small-block crate engine. Clean bill of health from Barker Machine in May 1, 2012 · These heads are the best flowing heads next to the w-2 heads mopar produced in the 70's. What should I look for as far as problems, I not a engine guy, so I could use some advice. 55 suregrip LT headers 1 5/8 Holley 4150 dbl pump Supposedly steel crank, haven’t been able to confirm if Oct 24, 2018 · Does anyone have experience stroking a . Get the best deals for Mopar 340 Cylinder Heads at eBay. 88I 110 165 190 190 185 1. Jul 20, 2015 · Hi guys, I recently picked up a set of heads at a swap meet that are supposed to be a set of 340 T/A heads. It has a J head on 1 side, and a U head on the other. 60 Exh. Nov 30, 2018 · Thanks Jadaharabi So if i am reading this correctly i have 360 heads not 340 heads judging by your photo and If the following is correct then 340 heads would be stamped 340 and on a 340 and 360 heads would be stamped 360 and be on a 360? "3418915 – 1970-1972, 360 LA-series small-block, 1. The T/A heads have identical porting and runners as any 340 or 360 head. in that case 'if it were me'I would be looking to remove about . X head. Might have been a few very early '70 models with them but the official casting for 1970 through 1973 was the 'J' 915 castings. There is a J cast into the deck facing surface, and up top, where the J usually is, there is a II cast. All bolt holes are the same. it came with 1. I bought a completely rebuilt 340, but only needed the shortblock. 88 valve ,for 360 and 2. 85 116 124 129 133 w/ MP 1. They are essentually a step down from teh 340 x-heads. Dec 22, 2007 · I have two sets of "J" heads and one set of "X" heads. To set the record straight, Mopar did put 2. valves were 2. i think it's just the way the castings came out. If I remember correctly you need to take a bunch off the 360 heads to make up for that bigger chamber, and then probably cut the intake to match. The heads were milled . For 1971 and 1972, 340 and 360 engines were equipped with 3418915 heads, so-called "J" heads, because of the cast-in J in three locations (backwards in one place) on each head. 6L/340 Cylinder Heads and get Free Shipping on Orders Over $109 at Summit Racing! Bare, 63cc Chamber, 171cc Intake Runner, Mopar, 318, 340, 360, Each Jun 7, 2006 · The stock Magnum head is an excellent upgrade over the stock older heads. I built the engine back in 1984 and used a 69 340 block and Feb 18, 2006 · Building a performance 340 to replace the 318 in my car. 88 int valve due to the back side of the valve head having less tulip to it. I followed the build almost exactly. The X heads average about 7 - 8 CFM more flow @ 400 lift than the J heads . 02/1. # 3418915, 65cc 73 Cast. 100 bore. They came with the 360 core I bought for $300. Although J heads are fine, the '576' is an updated design (as far as factory iron small block heads). My 340 was a '69 date coded 340 for 1970. Mopar uses the same magnum head for either 5. Shop now for fast shipping and easy returns! Sep 21, 2022 · [FOR SALE] 1972 340 J heads. 65-inch exhaust and 2. They appear to be basically the same. 95. The numbers are on the side of the block Aug 30, 2010 · The area of the chamber of a 318 stock head and a 360 J head is greater. Earlier heads are X heads which are probably the best small block chrysler muscle car era head, problem is they did not have hardened seats for use with nonleaded gas. They are ready to bolt on and go. Add a set of stainless 2. i'm just wondering if and what 340 heads change on the 360. yes the T/A heads are identical to 360 J heads except for, relocated pushrod hole, T/A mechanical rockers, & bannana groove rocker shafts. I'm now trying to decide what heads to use. 02 valves but never made it on the 360s, it was still a 340 head with the 2. Aug 30, 2006 · NHRA lists all this information and it comes from chrysler corp. in real world of stock and superstock, the 1. 60. Apr 16, 2022 · These are the real deal unmolested Mopar X heads off of a 340. Find top brands, exclusive offers, and unbeatable prices on eBay. The real question is how far bolting open chamber heads on your 318 is going to lower your compression. Part Number: TFS-61494080-040 Jul 30, 2019 · A bigger cam and higher compression will only take better advantage of the flow and turn better numbers than if you stayed with the J heads. Speaking strictly of how they perform from the factory, I think these are my #1. 63 cc (65 cc relieved optional) Feb 14, 2018 · So i have a 1973 Duster that was originaly a 340 4-speed. Clean bill of health from Barker Machine in Mar 21, 2004 · They posses decent flow for a stock casting and are generally the favorite casting to put larger valves in. Some '70 J heads are 360-2 heads. 60 inch valves, and have "open" chambers with volumes of 65-73 cc. 075 Tip Length: . 60 the seats can be ground to accomadate the bigger Jun 30, 2015 · Having established the correct pushrod length, Brian assembled the heads with IMM/Ferrea 6,000-series valves (2. 02 is because chev used them in their 327 and 350. The X heads can also be an expensive piece. 030 over 340. I am not sure if any of the other letter heads did. the chev head 1. - - - Updated Sep 6, 2013 · The factory 2. These are something even less Mar 26, 2007 · I think the casting numbers are 3418915. the X head only was used 1968 to 1970. car slowed down . 02 j heads also have an exact 72 cc chamber. 9 (360) Magnum which are prone to cracking issues. Mopar Cylinder Head Casting Numbers casting# year engine(s) Aug 25, 2013 · Bet you didn't know such a thing even existed. In fact (and testing supports this) the bigger valve will INCREASE low lift flow, which by all accounts will help with low end power. 88 / 1. Jun 30, 2015 · Having established the correct pushrod length, Brian assembled the heads with IMM/Ferrea 6,000-series valves (2. 60 valves, stainless springs, hardened seats and bronze guides and the heads will flow a whole lot better and will be very strong. Not sure how they could have the same casting number as the J head. New Oil Pan Bolt Set 20 , 12 point head Mopar 318 340 360 383 440 Dodge B RB LA . 82-1 Your 340 with the same head gasket as above with an iron head is, 9. The intake rocker was offset and the pushrod hole was elongated (to Jan 2, 2017 · Number one, welcome to the forum. The factory 2. Not even close to a dog. 88 valves are ideal. Read on our engine buildup as we take a 340 engine replace the hydraulic cams and stock rockers for 340 X heads in our 1970 Aug 9, 2017 · Has anyone got a 273, 318, 340 J, 360 J LA cylinder head combustion chamber volume comparison chart or advice. As I understand, J heads can come with both 1. ps, I had a pair of 915 Nov 7, 2001 · The problem with muscle car eras cylinder heads was the short side radius, or the lack of it. I've got a pair of 1972 J heads with 1. 5:1. Find many great new & used options and get the best deals for Mopar 340 360 J Cylinder Heads 3418915 at the best online prices at eBay! Free shipping for many products! One of my buddies has a 71 Duster 340 that came with large intake valve J heads, while my 72 340 RR came with SMALL valve J heads. These heads have unusual markings. 50 valves. 02 valves in a . 60 valves, 65cc-73cc" "3418915 – 1971-1972, 340 LA-series small-block, 1. chrysler had one head casting when the 360 came out, they machined the seat for 1. This video is for new folks to the Mopar sce Ok, here is the info I have on 340 heads, I hope that it is accurate, but if not, I'm sure someone can correct it. In fact, wouldn't be a race. But no reason that people can't link like they have been, and use the info to compare to I have a 69 10. This IS pump gas ratio land. 2268341 – 1962-1967, 318 LA-series small-block, 1. 02 j heads I have tested flow 228cfm intake and 142-147cfm exh. Find many great new & used options and get the best deals for Mopar 340 J heads at the best online prices at eBay! Free shipping for many products! Jan 27, 2015 · A 1968 340 has as much or more low end than a 1972 340. Apr 8, 2007 · hi, In 1971 mopar brought out the 360, they also brought out the J head/915 casting. These heads are NOt high performance heads but just sime dead stock heads. You can CC a set of "J" heads and have them milled to "X" head specs Apr 27, 2015 · the reason mopar went to 2. 88-inch intake (360) is also popular. I remember reading an article in 1989 in a hotrod magazine documenting a test of Mopar engines by the now defunct racing guys at Chrysler. 02-inch valve 340 high-performance heads are really tough to find, but the later 360 smog heads flow just as well or better with just a little work. Feb 23, 2007 · I talked to Scott Koffel abought fully porting my J heads for the 340 to 416 stroker assembly I'm mulling over having them do. T/A heads--and indeed, all 1970-'72 340 and 1971-'72 360 heads--are some variation of the 3418915 "J" head (the last alphabetic digit is meaningless) but not all J heads are T/A heads. their pretty much all the same. 88 vs 2. 15-inch intake valve is to be used, wide valve centers must be used. 600 360 "J"-#587 w/1. The "X" and "J" heads are the best production heads for the small block Mopar motors. Jan 15, 2021 · There is no mystery why the J head floor was cast the way it is. 88 for 360 or a 2. Apr 20, 2008 · J heads have the same ports as the 360 heads. Yes, the J heads will be a noticeable increase in performance, especially above 4000 rpm's. 88 intakes. 88 in a Find many great new & used options and get the best deals for Mopar 340 J Heads at the best online prices at eBay! Free shipping for many products! Jan 12, 2007 · Stock there are only marginal flow differences between all the common four barrel heads-unless you spend extra for a ta or x head and you could easily beat there flow numbers with a little work on any smog 360 or j head. 94 does same versus their 2. By 1973, emissions requirements lowered the compression down to around 8. Now, there is a solution to this problem. 2 or 5. LA Small-Block Mopar Cylinder Head Casting Numbers. The big key with the 340 in a low performance stock form is to get the compression up to at least 9:1. they should have the 1. Feb 28, 2020 · It seems these heads are actually pretty good shape. 88 intake valves. runs of the Js had the 2. Gives Feb 20, 2013 · Early J Heads have 202 valve just like X. To make use of the 340 cylinder heads, you will need a 340/360 intake and camshaft. 78/1. Mar 28, 2003 · i have T/A heads on my cuda, and they have J's on them. 88 intakes, and even if they aren't ported, less hassle than swapping to the Magnum heads. 02 heads on a stock 273 is a "oh oh" (bore size), and of course magnum heads will go on the older LA also but some mods will need to be done In short, 318, 340 & 360 LA heads are all interchangeable as far as bolt on. 0048 removed is 1 cc' on a 340/360 head fwiw. 7. 050 Tip Length: . Only put this ahead of the 308 because of the 2. 88/160. These are worth a lot of $$$. That would be a bit too much for 318. 400 . Some had 2. Note; Though 'not' the Optimal Flowing Head @ High-Lift or High RPM's, but for 'Street Performance' it is more than capable of performing well. The numbers tend to get inflated because of it. Has stock manifolds, 2. Needless to say I'll be picking up a set of Eddy's for my 340. TKS, R. 02's can be installed easy. We have a great online selection at the lowest prices with Fast & Free shipping on many items! Find many great new & used options and get the best deals for Mopar Dodge Plymouth 340 360 J Heads # 3671587 at the best online prices at eBay! Free shipping for many products! May 23, 2020 · Here is some comprehensive information on 340 heads A Guide To Mopar V8 Cylinder Head And Block Casting Numbers . 520/. unfortunately at some point in its life the engine froze and it cracked the 340 block. 02 or 1. lol I agree the 340/360 heads should be milled to raise the compression, they are 72'ish cc's from the factory with 318 heads 'open chamber' version being 68'ish cc's. 02s, I'm sure the X head was gone in 71 replaced by the J which was the primary heads installed on the 340/360, they shared the same In this video we take a closer look at our Mopar "915" J head 340/360 casting. We have a great online selection at the lowest prices with Fast & Free shipping on many items! Mopar 340 Cylinder Heads for sale | eBay Mar 24, 2012 · Many heads are referred to as J heads. Of the "J" heads, all but the T/As had 1. 50 valves May 7, 2009 · I know some guys that flow SB Mopar heads on 4. Mar 20, 2025 · Mopar Cylinder Heads & Parts for 340, Mopar Cylinder Heads & Parts for 440, Mopar Car and Truck Cylinder Heads and Parts, Mopar Car and Truck Cylinder Heads, Mopar Car & Truck Cylinder Head & Valve Cover Gaskets, Cylinder Heads & Parts for Honda Civic, Cylinder Heads & Parts for Toyota Tacoma, Cylinder Heads & Parts for Jeep Wrangler, Apr 27, 2022 · 340 and 360 LA heads have larger intake ports and are the only production LA heads worth using on a stroker engine. in 72, all were 1. . 02 converted heads are J heads. 020” valves. 880” intake valve, but they can be re-machined for use with 2. called keeping up with jones's . 02I 111. you can regulate the height of the valves in the head with the installation of seat inserts. Part numbers 3418623 and 3418621-4 Jan 8, 2014 · Edel makes 2 heads for a 340 because there were 2 piston deck heights used and the first edel head was a closed chamber design. These are suitable for restoring your 1968-1970 big-valve 340. 26-1. The port contours in the different 340/360 heads are very similar; the X nad some J-heads had the bigger intake valve but since the heads are exhaust handicapped in the first place there may not be a lot of benefit from the bigger intake valve. 02 valve 915 was the T/A So the date code 2990 comes out as Saturday - 10/4/1970 That would make it a '71' car cyl head The AAWJ and the cast "J" by the plug hole confirm - J Members stated above: My heads do not Nov 14, 2017 · 318 swirl port heads are to have the “302” Designation. 02 intakes , I suggest that you measure them , either way they are good heads with good sized ports and good flow, if these heads are the 1. 63 cc (65 cc relieved optional) Feb 28, 2022 · If you want to use stock J heads and only want 350 - 400hp, get a good three angle valve job on the heads, an Edelbrock air gap intake manifold, 750 cfm carb, TTI headers and the stock 340 camshaft! That way you can stay with your stock 340 torque converter. They're supposed to be unmolested, I haven't seen them in person yet. Some '73 "J" heads are 360-2/360-4/340 heads used from '73-5 at least. Or build a low compression 360. 88 valves were 71-72 340 heads. 5:1 compression. 02 and 1. They seem to all flow about the same. The vast majority of them are not. 60 inch valves, or 2. I currently have X heads on my 68 340 Barracuda. I knew a little bit about them before I bought them, like the casting number and "U" that is casted into them, but they have neither. Topped off with "71" 340 intake, TQ and the "72" 340 cam. 02 inch/1. Similar to the '71/2 360 and '72 340 heads. Kim Feb 26, 2011 · The 915 heads with 2. I will say that just bolting on a set of W2 heads Apr 8, 2019 · Im going to look at a pair of "bare" 340 X heads on Tuesday 4/9/19. 02 valves. 020” size. The heads were just reconditioned with a Comp valve job, teflon seals and have double valve springs. 02 intake valve heads have had a high $ full port and polish from Les Schmader. Jan 22, 2023 · Trying to decide money vs gain on either building up bare speedmasters or reworking my J heads, would use valve springs for my cam. Brand New. I’m probably gonna use them on a 340 with 10. Mar 28, 2004 · Hey guys, I have the chance to guy a set of 340 "J" heads from a freind. My 340 has J heads. 225 12 Deg Super Flow Exhaust Part# F5051 Head Diameter: 1. 020 valves. 02 valves, The J had the 1. Mar 11, 2019 · Having done the swap, I put 340/360 heads on "64" 273 . 02 valves (P4529269). And it had J heads. 02 intake valves into the magnum heads all the head research i've done, has lead to magnum heads being "better" than the x and j heads off of 340s. We have a great online selection at the lowest prices with Fast & Free shipping on many items! Apr 14, 2004 · hello, in 1971 mopar changed to 915 castings. 88 and 2. They came on the 68-71 engines, but the J heads can be machined for the bigger valves. the 1. # 3418915, 65cc 72 Cast. They have a flow rate of approx 200/210 cfm. Now I'm already planning on putting a set of LA-X heads with 2. 2532080 – 1964-1965, 273 LA-series small-block, 1. what do yall think . In fact, the head carries the 360 J casting number. 2 (318) and 5. Chrysler went with the 1. So many scare people by compression talk. The 340 valves’ head diameters are the most popular at 2. 88 340 and 360 are damn fast. 200 . A bowl hog and blend and a stock head will make great power on the cheap. does it increase Oct 15, 2016 · You are buying a pair of Mopar 340 or 360 3418915 J Casting Cylinder Head Castings. Sep 10, 2006 · you could always put the 2. 88 or 2. Flow bench results will vary! The "J" heads as far as I have personally seen come with 1. both were made with either 1. 60E 90 117 135 140 141. Jun 17, 2010 · A J head is a J head and they came stock on 340s so they will work fine. This is why the guy said you need taller pistons. Opens in a new window or tab. 030 over 340 w TRW 2316 forged pistons, lightened 340 rods w/ ARP bolts, and stock forged crank. Casting dates are 12/04/1967 and 12/05/1967. We look at the dampened valve sprin Apr 18, 2012 · I just bought this motor and was wondering what to expect from it and why would you put 340 heads on a 360 motor? Whats to pros and cons of doing this and are the 340 TA heads rare and better or worse then 340 J or x heads. $28. Thread starter Owen 340+6; Start date Sep 20, 2022 - M & J Body Classic Mopar Forum; Other Sites to Visit. 250" bore SB mopar. just food for thought. With some work they can be very useful heads. Oversize valves, such as 1. Bore, . On our stock eliminator stuff no flow difference between intake valves size(202 to 188) assuming stock ports. Home. 340 supposedly . 88-inch intake valves, but were also produced with Jul 16, 2009 · are those J-heads 1971 340 heads with a date code of 1970 or 1972 340 heads with a date code of 1971? If date code of 1971 I would check the size of the valves. 60 valves. Get the best deals for Mopar 340 J Heads at eBay. Oct 10, 2011 · wow. These heads are most often found with the 1. 5 pistons and a cam just around . Could have 2. There are several casting numbers on the block, but all should end in "340" if it is a 340 engine. Something more in line with what it's actually going on will get you a representative number for the bench, say a 4. '75 Dodge Power Wagon 600HP 340/418 Stroker Engine Sep 21, 2017 · A . Magnum heads. They are refurbished and ready to bolt on. Same as the X heads. 02 valve for the 340. i wasted alot of money on these heads in the early 90's before anything else was available or i knew Mar 6, 2003 · Have seen 10-12 k engines come apart because they spent all their money on the lower end, then went to a rebuilder and bought a set of exchange heads. 30 over 915 J heads- unmolested Crane cam 284 H12 pt# 150062 Eddy Air Gap intake 4spd w/ 3. 2465315 – 1964-1965, 273 LA-series small-block, 1. Here goes: 68-71 Cast. cuda is right , for good performance, expect to spend from 250. 88/1. Jan 31, 2018 · He continued to say Mopar used some of the best seats available back in the day, and to this day he would starve if he had to rely on Mopar valve jobs, or rebuilds. 56 valves. 30 over, Speed Pro Forged pistons- L2316F, J heads, Crane Cam 150062- Flat tappet (Crane Cams 150062 Crane Hydraulic Flat Tappet Camshafts | Summit Racing) and some bottom end work done- to what extent not sure. 25 rear with 2. Aug 30, 2018 · The two locations in which you can find the casting numbers on Mopar cylinder heads. both 915 castings with 2. The difference on the T/A head is in the push rod area. If a 2. 6 valves is too much for a 318. 050 from the decks, 'every . 5 360 "U"-#915 w/2. Intake Port Volume. We compared bare heads, and there was absolutely no difference except the valve size. Besides, 340 heads are the same thing as 360 and factory AHB 318 cars came with 360 heads that used 1. I am asking $1200. 4 tenths , i wasn't a happy customer, like rumblefish said i guess due to heat disapation which they say lowers your compression a point and the single plane to, it wasn't a good switch. 60 inches for the A-engine. Second, the T/A head will bolt up to any LA series engine: 318, 340, 360. They are very well built. The 340 was way under rated by Chrysler. I have had many parts for 20/30 years that I can use in a 340 or 2 or 3 and maybe sell them off. The Edelbrock RPM cylinder heads for all small block Mopar engines come complete with valves and valve springs installed. Just take them to a good machine shop and have them perform a good valve job and port them. The Magnum heads are on the MoPar create engines. The 1. Feb 16, 2018 · Don't get carried away with J or any other small block mopar head you have 318 style and 340 360 style ports and a couple of valve size choices- all obsolete are the guides bronze or just knurled? new seats? what materiel- it does make a difference springs have dampners- that's a clue You are better off finding a set of the "swirl port" heads with the heart shaped chamber https://www Jan 30, 2020 · My AAR 340+6 came with 'J' heads, 2. 97 119 126 129 131 Early W-2 w/Prod. You'll be right around 375 hp. 60 valves stock. Head. Oct 6, 2015 · I thought the X heads not only had bigger intake valves but they flowed better than the J heads. These 2. Not a tire shredder, but spirited, fun to drive. 02-inch intake, 1. I can get a set Jul 27, 2020 · Best Small Block Mopar Aluminum Heads Overview. The 894 'X' castings were used on the '68 and '69 340's only. We look at the 1. 60 valves" Now being Aug 23, 2017 · Further, let me add that small block heads interchange, with just a few small details including early 273 heads having different intake bolt hole angles, 2. 250" bore fixtures. 02 308 head. They were from 1971 340 "J" on top and have factory 2:02 intakes. Know of others. 25 pipes, Performer intake and a Street Demon 625. 88" intake valves. 020 Steam Diameter: 3/8 Overall Length : 5. The X-heads are stripped, no valves and no rocker assemblies. 28-1 and with a 63cc aluminum head it is 10. 35 delivery. The do have the pushrod holes drilled correctly May 31, 2010 · All open chamber 340/360 heads with the expeception of the 308 head (these have the improved exhaust port of the magnum head) have the same chamber and port design, the air injection holes in the latter heads have no impact on the potential of the head (just plug them with epoxy or pipe plugs). A brief description of 894 X heads, and 915 J heads. ) Nov 14, 2017 · 318 swirl port heads are to have the “302” Designation. Sep 21, 2002 · No, you will not have J heads. 9 engines so the flow is there. Sep 16, 2017 · For Sale- Nice pair of 915 J-head castings for a 340/360. I have a 70 340 that is the numbers matching motor for my 70 Challenger A66 car, that has never been apart. # 2531894, 63cc 70T/A Cast. Sep 25, 2003 · Here is some flow data on some heads I had around 10 years ago: Head ID /Valve Lift> . In 70 the 340 TA head is casting 915 and that was the only thing that used the 915 casting. Also as I understand, 1970 340 Challengers came with J Heads. after i then ordered a custom grind cam May 1, 2006 · The "X" heads and the other 2. Any help with these questions would be great. 88 (for the most), but its very possible some of the 1st. 2. 02 valves allready installed and he wants $450 for em. Free Nov 1, 2002 · Tune in for more details and photos only in Mopar Muscle Magazine. J heads were in production up to the early seventies and came in 340 and some 360 engines, valve sizes were 1. Dec 3, 2019 · Small Block Head Flow Chart - Discussion Discussion thread. You can buy them bare if you would prefer to use your factory valves and springs. Sep 23, 2007 · 1970 340 High Performance Mill Dyno - Mopar Muscle Magazine It originally showed up in Mopar Muscle Magazine. Explore a wide range of our Mopar 340 J Heads selection. Jan 11, 2014 · Note; The Exhaust Port is found to Flow at {-6%} less on this Head than the 'X-Head' or 1971 340 'J-Head' @ Optimal Lift. Jan 10, 2009 · If your looking for accuracy I would cc the heads after they have a valve job,otherwise its just guessing,especially if the history is unkown. How many of us have a 4. differnt intake valves ans valve springs. You can't really grind out a J head to an early 340 head because they are already basically the same thing. In this video we take a closer look at our Mopar "915" J head 340/360 casting. The X heads all had 2. May 1, 2017 · Head Diameter. Some '70 J heads are 340 T/A heads with provisions for offset rockers. They will work great with your headers and intake and carb. Unless the block was 0 decked to the pistons, aftermarket pistons were limiting the distance below the deck, or the J heads are shaved, measure the compression or it will be lower than stock. 3. $400 for just the pair of heads. High Performance Mopar magazine, 1989-93 587 340/360 1973-74; 1976 596 318/360 1977-83 915 340/360 1970-72 974 360 Jan 26, 2023 · They aren't $50, far from it. food for thought, when going from Oct 25, 2006 · The 340/360 large port cylinder heads are much more desirable factory units for a performance build. 02. Marking on my heads are 3418915. now it has a 360 out of a 1980's Ram with the 73 heads on it. com Oct 2, 2019 · So if you go by this chart what 2. Though others have found the earlier heads to be super close and perform equally stock or ported. It says it wasn't until 72 that the 340 got the 915 head. 040 over 360 is just a stroked 340 some pay big bucks for a stroker and you already own one put the money in the heads ( at least magnums) YOU should not spend money on stock J or X or whatever iron heads- (I have some with new guides and exhaust seats but I do not recommend them today unless you are doing some matching number deal) (unless Apr 16, 2022 · These are the real deal unmolested Mopar X heads off of a 340. It runs great on the road and around town. 88 intake valves that need to be done over. all X heads had 2. 00 forged crankshaft, scat rods, 585 lift cam, Victor 340 intake, 11:1 Diamonds, worked 950 Holley, etc using ported J heads? What would be the HP limitation by using these? Only asking because I have the chance to save over $1k by May 17, 2014 · Flow trumps compression. "Some" J heads had 2. they wouldn't allow a 1. So you can probably assume that I have the 2. Not a big deal. 5 160 204 231 228 Early W2 w/ MP 1. 600 Steam Diameter: 3/8 Overall Length: 5. 88 - 1. Open chambers have a Mar 4, 2019 · The EQ Magnum heads are a direct replacement for the 5. 40 over 340 with a 4. 84/1. They could have been milled,the valves could be a bit low in the seat,its really a shot in the dark. 02 valve. The engine was in my 69 swinger when I bought it in 1981 and the rest of the engine was stock unmolested 1971 340, forged crank and all. I installed the large valves in my J heads and didn't notice ANY difference from before. What are the advantages of these heads over my stock 360 heads (on my 360 ci motor) They have the 1. I can't remember if its the X or J heads that have 2. Shop Mopar Cylinder Heads & Parts for 340 with eBay Guaranteed Fit. 500 . The motor is going into a 1972 dart btw. 02 valves and "x" heads with the same sized valves. 02 was only offered to keep up with the Jonses (Chevy) valve size offering. 60-inch exhaust) and IMM's solid-roller cam spring kit, which Jan 19, 2013 · I would use them. 6 onto a 318 (was originally building a 360) I will Oct 9, 2012 · casting # 3418915 used on 1970 - 340 6Bbl T/A also on 1971 - 360 also on 1972 - 340/360 1973 used different casting numbers , you may have lucked out and got pre 72 heads - the good ones with 2. 02 valves, pushrod holes relocated and the adjustable rockers, so Ma Mopar definitely had them out for the 1970 model year. 500 lift or alittle more. 02 valved J heads on 1970 340 cars, because i had such a car, and its far from a oddity for this to be the case. Also included is a ported and matched Mopar M1 aluminum single plane intake manifold. 02 for a 340. 171 cc. My matching numbers 70 340 Duster (B3) had 54000 miles on it when i got it. 040 over. 71 gear all in a 76 Aspen wagon. He told me a set of Edelbrocks will flow more out of the box then my J heads would ported. 60E 95 129 138 140 141 W-5 w/Chev. How to identify and what year and engine they were used on. Which by the way came with 1. # 3671587, 65cc ok, that one has me stumped. 08-inch intake, are also common. ps, I had a pair of 915 Aug 30, 2006 · NHRA lists all this information and it comes from chrysler corp. 118 166 190 196 193 w/ Prod. In 71 only the 360 got the 915 head (small valve). (Also IMO because it was the current head being casted. Sep 4, 2003 · The "J" heads were those used on the '70 T/A 340 Six Packs, as well as the 1971-and 1971 360s and the 1972 340 only. Mopar Commando LA. Let me tell ya, a 318 2bbl with 9 to 1 looses to a 318 4bbl, J-heads and headers with 8 to 1. 02 valves, right? Here's the mystery: they are blue. 02 intake valves. They will have the EGR port plugged already. Feb 11, 2009 · 70-72 340 heads. Buy It Now +$6. 040 and . 038 on the intake side to min cc, 64. Mar 5, 2015 · The other letter heads "O", "U" , & "J" are standard pushrod holes heads . 02 wth the 340. got the 340 good stuff- cam,intake,J Sep 19, 2023 · W2 short valve (close to stock length) econo valves Intake Part# F5050 Head Diameter: 2. Massive selection from top brands on eBay. I bought it minus the heads. 080 in. J heads are the best platform to start porting and doing mods to because the floor is different /better also there are J heads for 340 from the factory, and for 360 from the factory. Jan 18, 2021 · The Mopar/Chrysler LA 340 that got everybody’s attention in 1970 was a hot little small block with good heads and 10. Not many that's for sure. High Performance Mopar magazine, 1989-93 587 340/360 1973-74; 1976 596 318/360 1977-83 915 340/360 1970-72 974 360 Jun 11, 2007 · had a set of self ported j heads and air gap intake, then switched to a set of stage 1 eddys from hensley and a victor 340 intake nothing else changed. Clean bill of health from Barker Machine in Nov 21, 2019 · Unless they are TA heads nothing. These aren't very special. 02 Int. The X head only ever came with 2. To make up for the compression loss (because of the 340/360 open chambers), you will also need taller pistons. 300 . Jan 24, 2023 · Currently, car is a 73' 340 . We look at the dampened valve sprin Comparing LA cylinder head flow numbers. its called cost cutting. May 31, 2019 · I have a 340 in my 67 Barracuda that came out of a Duster (not sure exactly what year, I've been told 72 but maybe a 73) but that irrelevant because the heads on the motor are not the originals, the car came with an extra set. Really only difference is valve size. 02 heads did 1971 340/275 Hi Compression 4bbl motors have? Back to these-3418915C 2990 AAWJ 3418915-C - if you look at the chart below the only 2. I really wish I had enough money to pop for the B1/BA heads though!!! Mar 27, 2008 · But according to my "Small Block A Engines" manual from Mopar the 894 X head was used from 68-71 on 340's. Apr 16, 2015 · The more I'm reading and learning on here (which is a lot) I'm getting the understanding that using 340/360 heads or any heads with 2. You can get a cc kit or just pay a shop to do it but its money well spent,Ive seen j heads from 68-72 range without milling depending on the valvejob and Mar 25, 2014 · - - - Updated - - - and Yes the J heads do offer an improvement over stock 360 heads ESPECIALLY over the smog heads NON-swirl, biggest difference is the smoother softer radius, leading into the Valve pocket (intake) and a cleaner radius out of pocket on exhaust, there is also a difference in the floor and side walls of runners both on intake Dec 28, 2017 · The biggest difference I have seen between X and J heads, is about $300 a pair! LOL. Horsepower gains are tough to predict, but you will gain power. Feb 27, 2021 · All J heads use the same casting; the T/A heads require special intake rocker arms not used on any other cylinder head. Great deals. Guy kept them. You will need to have your valve springs or any new springs that you buy checked for symmetry. But, unless they are TA heads, the only difference is either the 1. Ported edelbrock 63cc heads (flow 275 @ 600), Comp XE282S (. spacer, and Holley 750DP. Not measured, but by area, maybe twice the size of the 318. 88 flows very well, has better port velocity. 00 for head work, depending Jan 14, 2019 · All small block heads use the same valve spacing, so this is true for all LA and Magnum heads. 60 and 2. 02 intake valves, and the final approach of the floor into the bowl was shaped to meet up with a bowl sized for that 2. Jan 8, 2014 · im no head expert but from what justin used to tell me, unmodified X heads are the ****. This is an added bonus for street performance and reliability. A fully ported J head can approach OOTB W2 head but a well ported W2 should go 300+cfm. they are factored Jun 10, 2013 · The 340 and 360 used the same heads so for a stock setup, mild performance, out of the box and clean will work fine. Comparing LA cylinder head flow numbers. Has a stock 904 with a 8. 88 inch/1. C Body Mopar Tech Forums. Get the best deals for Mopar J Heads 340 at eBay. There was also a ported version. I've read that the 'J' heads were originally cast for the upcoming 360 engine, and it was a toss up which the '70 340s came with. 1. 360 heads on a 318 will really wake it up but remember to mill them down to get your compression back. The J-heads are actually one J-head and one U-head, both 915 castings. Dec 10, 2021 · Was on a thread on facebook forum guys were talking about the different 340 head offerings. This is a VERY NICE SET and has been professionally cleaned, shot blasted, magnafluxed and verified to have no cracks or damage. 00 for them. Apr 22, 2021 · The ratio went to 10. Chamber Volume. 02 valves were 70 only for the T/A and the 915 heads with 1. My Challenger was produced in November of '69. Also combustion chamber centering to block is much better on X heads. The 68cc head will be approximately @c after milling for straightness. 225 14 Deg Super Flow W2 long valve heads - econo version and W2 / W5 race versions with flat pedestals for use with offset Jan 26, 2023 · They aren't $50, far from it. What is the difference between a set of "J" heads with 2. Forums. 1 340+6 T/A heads are "J", "O", Jul 4, 2018 · The '70 model 340 heads were the 'J' 915 castings and they came with 2. 88 valve heads. The 73 340 heads had a casting number of 3671587 A lot of this information is out of the Mopar Chassis Guide which I would not recommend trying to get through life without. There is absolutely ZERO data that supports a loss of low end power with a 2. I used "72" 340 "J" heads with 1. Notice that most 2. My dyno results ended up being 410hp/412tQ. It is my understanding that this was the only year that they had 2:02 intakes on this casting. Standard fare known as J heads to most. Classic RoadRunner Forum; Feb 20, 2025 · Here is my list, in order, to the best performing factory small block heads as cast from the factory (273, 318, 340, 360). 02 intake valve size. com. If you're going for an accurate restoration, these things are a must have. Here's the page from the Mopar Perf Head Gasket, Multi-Later Steel, MLS, 4. 88 for 360 and 2. I have a early 360 short block that I want to put together for my 66 B-Cuda. 2 Feb 28, 2022 · If you want to use stock J heads and only want 350 - 400hp, get a good three angle valve job on the heads, an Edelbrock air gap intake manifold, 750 cfm carb, TTI headers and the stock 340 camshaft! That way you can stay with your stock 340 torque converter. I'm sure the most valuable blocks, or engines, are the TA or AAR pieces. The 302 has a slight advantage and thus is the reason MP used that head for there performance ported 318 head. Supposedly the "X" heads have slightly smaller combustionn chambers and will make a bit more compression. Compressed Thickness, Mopar 318, 340, 360, Each. Mopar Performance Specs. I'll add any flow numbers contributed by a member, but I don't want to take info from someone else's website if they haven't given permission. 340 heads have a larger intake valve with a 2. they all came with 2. Oct 11, 2015 · I have a Comp XE 262 with KB pistons and J heads with 2. May 16, 2019 · 318 intake ports (cylinder head & intake) are much smaller than 340/360 intake ports are. The head swap requires AMC style lifters which have an oil hole for pushrod oiling, proper length hollow pushrods for oiling the rocker gear. I have had an original pair of 915/J heads with 2. 040 in. ) Sep 19, 2006 · The X head had the 2. 02 valve in anything lower than 6500 rpm is a torque/HP killer. 360 heads use a 1. Casting number 2531894 - 1968-1970, 340 LA-series small-block, 2. Find DODGE 5. I also have a set of hp exhaust manifolds off the same motor. 88 valves on 1972 model year through 1973 of the 340s. The port volume increases from 160 to 165 with a 1. 00 to 1000. port speed is what feeds the engine. These were either equipped with 1. Apr 26, 2017 · I have a set of rebuilt 340 J heads (3418915) 2. Jan 1, 2017 · Don't know for sure about the 340 J heads, but uncut 360 heads on a 318 lowers the compression a ton. 8:1 . If your's has a july 70 on it, probably an early 1971 motor. The heads bolted to the motor are both (360) J Heads, casting number 3418915, AAWJ. 540) solid flat tappit cam, Comp roller rockers, PRM air gap w/ 1 in. 88 valve head on a 1971 340 period. All the ports and chambers are pretty much the same. The T/A head. 340 branded head was open chamber for pop up early 340 piston. fnxek zdbsx ccdg faxhbswhs bgit nmqp hpkfz xyxaiaji gczkssom lvzrt