KCBones
Well-Known Member
Definitely a J and a U. I looked them over pretty good when I got them back to my garage.
X-heads or J-heads on a 360 LA Engine
- Thread starter KCBones
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Still the same heads.
Say you’re near maple grove, I live outside of Allentown towards Kutztown. Maybe see you at some shows this yearIt isn't that they (X heads) are special they are correct for a 68-70 restoration on a 340 A body. Not everyone with these cars is building a race car or need an aluminum top end because "that's what guys on the web do..." people are still restoring these cars not every A body Dart with a tail stripe is a clone car
They are also worth more than 50 dollars as are J heads. Folks putting out there that they aren't are just wrong. Again not everyone is a racer I can go to my local race track Maple Grove Raceway and see it... there aren't that many racing and next to no one watching so yeah...why push race bullshit when it isn't reality.
stroked340
Well-Known Member
Neither I wouldn't put 2 cents into iron heads..been using aluminum for over 15 years will never go back to iron heads unless they're a nice set of W-2's..
KCBones
Well-Known Member
I'm a bit more budget oriented on this car. The only aluminum heads that would even come close price-wise are the Speedmaster heads and I don't know too much about those.
68 -69 some early 70's had X/894 heads. Most 70's and all 71's had J / U/ O/ Z heads they were all 915 with 202 valves . All 72 8.5-1 340s came with 915 heads with 188 valves. If you are running a full factory exhaust the 188's are all you need with 9-1 comp. Are 202's better? I asked my wife she said bigger is always better.
Dartswinger70
Well-Known Member
Sure 2.02s are better, I wont argue that . But 1.88s will do for a stock resto street build on a budget. They can always be punched out to 2.02 later. I have 2 sets of 2.02 heads I'm good. I may pick up more if I come across them and the price is right. According to some here they should be scrap price LOL! 
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KCBones
Well-Known Member
The early intent is to run headers, 2-1/2" pipes all the way back (maybe an H-pipe), 9.5-1 compression. I'm just starting body stuff so everything is subject to change but that was the intent when I started. I'm using the Edelbrock Performer and Holley 4160 600 cfm carb that was on the 318 in the Dart when I bought it to save some money.
Dartswinger70
Well-Known Member
Yeah the j s will work for you for now. you can swap to aluminum later its a Saturday mornings work to swap heads.
Did you know 340's in 71 came equipped with an 800 cfm. I never run anything smaller then a 750 on a small block . It only flows what it needs why strangle it at the throat.
KCBones
Well-Known Member
It just happens to be what I have at the moment. Hopefully someday I can upgrade it.
340sFastback
Well-Known Member
I ran a Holley 600 on my stock 340 years back it worked well once I jetted it up, changed accelerator pump nozzles, accelerator pump cam, played around with vacuum secondary springs ect. I believe that Performer intake is small port where it meets the heads but maybe it can be gasket matched to the larger intake port J heads that is something you will have to look into? 360 with J head once the compression is up and some cam can make some nice power great street engine.
340sFastback
Well-Known Member
If you have money laying around and "want" the X heads and they are in good shape good price, yeah they aren't any better then J heads, but you know the X on there is cool.....
Rat Bastid
Dunamis Metron
Not all 72 340’s came through with 1.88 valves. Some of the early 72 340’s came through with 2.02’s. And 10.5:1 pistons.
You're sick. Proud to know you. lol
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