Am I an idiot for wanting to boost a high compression 318?

dusterbuster5621 said

I actually do have a pair of 360 heads on the engine. My dad always referred to them as police engine heads but I haven't taken the time to remove the valve cover to check out the casting number. (But now that I am saying I probably will tomorrow) The heads were milled down by like 0.100" to get the chamber volume down. I vaguely remember measuring the volume and it was around 65cc (this was over 10 years ago). The intake had to be milled down to fit as well

Click to expand...

Are you running domed pistons in your 318 to get the compression up to 10.3:1 with a 65cc head?
My 318 (+0.060") works out to 9.8:1 with a 63cc chamber and flat top pistons 0.013" above the deck. If your compression ratio is a bit optimistic it will make things easier for you.
Either way you will need to open the motor up to enlarge the ring gaps, so good to verify what your starting with and you can adjust your final compression ratio by cleaning up/enlarging the combustion chambers and/or head gasket selection. My daily driver has 10.5:1 static and is fed a max of 14psi from 2 snails but that's new tech (alloy motor, direct injection, VCT ect ect with a million sensors to pull things up when something is not happy). Not sure I would try doing that with a old 318 without a LOT of previous experience building & tuning boosted motors. 8-8.5:1 and 5-7psi is probably a good place to start.
Having said that the easy button for a reliable 400hp would be a 408 crate motor - might even cost less