318 advice

-
M

mattydean

Well-Known Member
Joined
Aug 18, 2007
Messages
104
Reaction score
1
Location
arizona
I know the 318 subject has been beat to death, but here it goes. Finally starting on my 1967 Barracuda with my son. I will be taking the slant 6 out and replacing it with a 318. The engine was a freebie. The privious owner got feed up with his project when he found it to have a rod knock. I took it apart and found 2 cam bearings put in wrong and the wrong size rod bearings. I took the engine down and had the rods resized, new bolts, and a polished a crank I had on the shelf. The rotating assambly was balanced. The engine is a fresh rebuild.

My question is how the following combo will work (this is what came with the engine) or what changes are needed for a more efficient ride. This will be a driver and we would like it to have a litte thump.

The block 0.60 over
Deck height to piston 0.80
Stock heads casting number 2843675-21
Cam is a Mopar purple cam p4452992
318/360 intake manifold
Carter afb new 9605 I believe 600 cfm
 
High 14s with a 26" tyre and 3.5 gears IF you run headers:-D

- the stock head will hurt you. Moper R/Fish or BJR will tell you what you should do with the heads......
 
Thanks I figured heads would kill me. Just not sure Ill try those two and see what is best.
 
Off hand, I can not think of the Pirple cam specs. Headers allways help sound and mufflers of course. BJR can tell you how much to mill the heads. Your ratio is about 8.5-1 with that piston down .080 and assumed head chamber of 65cc and a 4.06 X .028 gasket, (or close to it) which would be the stock head gasket. (AKA MoPar thin head gasket.)
 
Thanks guys.

BJR liked the site makes a lot of sense. Does Head Casting make a difference ie 302 or just use what I got and clean them up?
 
I guess it really depends on how much your going to street drive the engine, if it's going to be mostly street and some race then the 302's would be best. But if you plan on running different pistons and more race then the head isn't as much a factor, because the quench distance can be achieved either way. Both the 302's and the eariler heads can be made to flow the same. So port volumes and flow's are similar.
 
I'm running the same 4452992 cam in my 318, Idle quality is pretty poor,(10-11 inches of vacuum) The car runs good at wide open throttle though!
 
Thats pretty much the same cam as the 280H from comp. it should ahve about 14" of vacuum, check the idle mixture screw settings. Get a vacuum guage and hook it to the intake at a good vacuum source like the brake booster line, and set the mixture screws to get the highest reading and it should make a difference in the way the engine idles. If it doesnt then the valve springs or the valve job is weak.
 
BJR the 302 head with the bigger exhaust sounds like the way to go. talked with the machine shop and he has a pair he will swap my heads for. I will clean the deck a little. This will bring the compresion ration to 8.7- 9:1 in

Thanks everyone :-D
 
mattydean said:
This will be a driver and we would like it to have a litte thump.
Click to expand...

To me that combo would have a decent amount of thump without modification. But you will love the 302s, I bolted stock ones on my engine with a bigger cam and it felt really good, balanced power from idle up. I think I was only pulling about 8-10 vacuum at idle.... needless to say my engine is apart getting a little bit freshened up. :)


Also how much are you taking off the heads or are you just doing the block deck? I want to clean my heads up a bit and gain a bit of compression but I can't spend a fortune right now.
 
You must log in or register to reply here.
-

Back
Top