340 cam in a 318

Dan the man said

I would like to see true budget performance tips for a 318, 340 / 360 cam, intake manifold and carburetor cfm, headers or exhaust manifolds, 2 1/4" or 2 1/2" exhaust. Gear ratio, which factory heads will do, etc. I have a budget to follow and I'm only wanting to add a little extra zip to the 318. Thanks everyone for your help and advice.

Click to expand...

First add dual exhaust...

Then upgrade the cam, intake, and carb...


You will not get the full benefit of the cam, intake, and carb until you have dual exhaust....

2 1/4" exhaust is fine for a 318....


If you throw a set of 340/360 heads on a stock 318 bottom end, your compression will be down to 7.5... I've done that and measured it...

Either throw a set of 10.5 compression pistons in the 318 with the 340/360 heads to get you down to 9.2 compression, or install the 66 - 67 273/318 heads....

The stock 66 - 67 273/318 heads (casting number ending in 920) have closed chambers and will increase compression about .5 from the later stock 318 open chamber heads.... I'm currently putting an engine together with those heads... My head guy ported the 920's and installed 360 valves in them 1.88" intake and 1.60" exhaust... With a .040" thick head gasket, I will end up around 8.5 compression...