Dumb questions #178, 179, 180 I've asked this year...

-

nodemon

FABO Gold Member
FABO Gold Member
Joined
Mar 21, 2015
Messages
1,130
Reaction score
596
Location
St.Louis
I bought a 71 318 with j heads.. I was told it was a running engine, I'm assuming running good. He pulled it in favor of a 340 he found. Anyway, along with the j heads, it has an Edelbrock Performer RPM intake and an Edelbrock 600cfm... No idea what the internals are...although, I can see it has a double roller chain that feels good and tight. My question is, I have a fresh set of 302 casting heads, an Edelbrock LD4B intake with a Edelbrock 650cfm laying around..should I install my setup in place of the j heads and currently installed intake and carb..? Not knowing the cam situation, would I need to worry about my fresh set of 302's and the stockish springs..? Also, I've seen some confusing threads about what head gaskets to use.. Is there really a major concern when it comes to picking gasket thickness..? "Back in the day" this was never even a question... just went to the local parts store and asked for this part for this engine, etc..
I have a Mopar gasket kit that came with the 302's I bought, but the thickness is .050" to .053"..and I've seen where people recommend .028.. Where did simplicity of the old days go..???
 
If it were mine this is what i would do. I'd first degree the cam and see what your working with check your lift centerline and degree opening at .050. IF the head and everything is still on id do a cranking pressure check if your cranking pressure is low id pull the heads and start checking further. Id measure the piston height if its stock pistons and a stock block its probably somewhere around .08 in the hole then id cc the j heads and calculate the compression using the .050 headgaskets. More than likely you will be in the mid 8s if you have one cylinder that has an extreme difference im cranking pressure i would check the valves to make sure they are not leaking and are seated if all is well id dig a little deeper and check the rings. You will get more compression out of the 302s but the j heads will flow better. Depending on the cam id make my decision compression vs flow. If it's a small stock cam id port the crap out of the 302s and maybe even have them milled to bring my compression up some. A large cam with low compression is gonna be a dog on the bottom end. So at that point id probably pull the cam and start over. Your cam is gonna dictate your springs and valve clearance your not gonna be able to run a 508 lift cam with stock 302 heads. You will have to cut the guides replace springs etc. If it turns out the block has been decked and you have after market pistons and probably run the j heads and try to get the compression into the 9s with a mild cam 450-490 lift and 260-270 duration. That would be a fun 318
 
I'm sorry, you have asked too many questions this year and are over your limit...

You must wait until next year to ask any more....
 
I'd either run it the way it is (maybe try your 650 too) or tear it down to see exactly what you have and go from there.
 
I already posted in one of your other threads that a 318 with stock pistons and J heads will end up at 7.5 compression...

Askhole B.jpg
 
I wasn't asking about compression..
If I was going to the trouble of tearing it down and swapping heads I'd at least try to figure the compression to get the best combo if not just run it like it is and don't even open it up
 
If it were me, I'd load it into a car and drive it!! If you are happy with it, you're a winner, if you don't like it, then you can tear it down and correct what you think is wrong. Remember KISS! There is no need to spend money, time, and effort unless you KNOW something isn't right. Tearing into it is just creating a pile of used parts from a running engine.
 
-
Back
Top