i have a 283 with 041 heads milled .035. that should be about 58cc's, right? it has flat top pistons with 4 valve reliefs, and felpro head gaskets that are about .040" thick i think. as far as you can see by looking at it the pistons look like it has about 0 deck height, it could be about .010-.020 i guess. that would be about 58 for the heads + about 8 for the gaskets, and about 4-6 for the valve reliefs leaving it at about 62-64cc without factoring in the deck height so that would be around 9.8:1. do my numbers look right? what do you think the ccs for the deck height would be and my final compression ratio? just trying to figure out my compression ratio.

also, i've been running 89 octane with no problems. the thing is that i don't know what my timing is exactly. the key in the crank for the damper ripped out so i had to cut another one and i don't know where TDC is any more. do you think i should try 93 octane and advance the timing more?

i also have a cam with 204int/214exh duration at .050 and .422int/.444exh lift if that helps. thx