My goal here is to get as much HP as possible using the parts I already have. I want to keep it simple and inexpensive as possible.

I have a fresh.040 over 318 shortblock.
Stock height pistons with valve reliefs.
cast crank
The cam is a purple shaft lift 508/508 duration I think is 292/292
Stock mopar adjustable rockers
Windage tray
Double roller timing chain
650 Carter
Clutch fan
1 5/8" headers
2 1/2" exhaust with "X" pipe.
FBO ignition

318 smog heads (not 302's)
OR
360 small valve heads (flow 230 at .500)

Eddie performer intake
OR
Stock 360 4bbl

If I break parts I want it to be cheap to put the engine back together. I am thinking about shaving down the 360 heads and intake to make CR 9.5 instead of getting high dollar pistons, is that even possible?

I know the 318 heads will have better port velocity but that is alot of cam and the 360 heads are at least small valve heads.

I don't want to get into the transmission or the rear here, only the engine itself. I will start other threads for them when the time is right.

Smog 318 heads and the perfomer? 360 heads and the stock 4bbl intake? Mix and match?
Do you think I can get 350-400 HP out of it?
What are your thoughts?

I think youd be further ahead to look for the 302 heads, but if you stick with the 360 heads, youd almost have to mill them down to gain anything. also, with anything more than stock of a cam, id recomend getting a higher stall tc assuming your running an automatic. also stay away from single plane intakes and try to find a good duel plane like the Eddy LD4B. I don't think youd gain very much with the adjustable rockers either, but get the 340 springs at the least. with the right combo, you might be getting around 300-320 horse IMHO.

heres hot rods 318 build. lots of info here http://www.hotrod.com/howto/113_0304_318_small_block_build/dyno.html

I ran that same cam in a stock 360 and it wouldn't work with stock valvetrain because the base circle of that cam is too small so you either have to run adjustable rocker arms or adjustable pushrods. I ran adjustable arms and a 2500 stall and it ran pretty good but the stall didn't work very well until I added a trans cooler. I imagine it would behave the same in a 318 but not positive, maybe the mp purple cam will be fine in a 318 but it wasn't in the 360 and took a bit to figure out the prob. Just something to think about:)

The two intakes I will be choosing from are listed above. Which would work better for me the edelbrock performer or the stock 360 piece?

As stated above I will be using adjustable rockers from ma mopar.

Thanks for the article, that is the one that got me thinking in the first place. I tried to use a little more cam and my heads flow about 12 more at .500 than theirs do.

Does anyone know how many cc's these heads need to be to get my CR to 10 to 1? The pistons are stock replacements with valve reliefs.

Your biggest problem in regards to acheiving your goals are the factory pistons.You need to get some zero deck KB'S or similar.The factory slugs are always 40-80 thou down giving low compression.Those 360 heads are generally between 63-72 cc's.You need a zero deck\piston and 54 cc's to get 10:1 with say a .039 gasket.The KB'S are a good way to reach zero deck without massive decking of the block and they have good valve reliefs.

Though this does take away from truelly inexpencive; angle mill your 360 heads (you were/are contemplating cutting them any way). You can get your compression ratio up into the 11 to 1 range ( you can go less ) with a stock piston down in the hole. You would need to re-eyebrow your pistons for valve clearance.

I've got a teen built like this with an even bigger cam (Comp XTQ281S). It took my Barracuda 12.54 at 107.6 mph in the 1/4 with a too tight converter and less than ideal rear suspension.


If nothing else, this gives you something to think about.

Good luck.

Jim Burch