ok ive got some dome pistons and some almost flat top pistons for my 350. with the domes the motor would have around a 10.5 :1 CR with the others it would be a little over stock i think a 9.2:1. this motor is gonna be in a bracket car. it has ported 193 heads with the stock 1.94 valves and probaly roller rockers. the bottom end will be stock and this is going to be mated up to a 3 speed. ive been told the 10.5:1 CR isnt real streetable which could be an issue for me. if i use the flat tops and buy a good cam accordingly what kind of power can i expect as compared to the domes?

 

well my first question is 193 heads are 64cc chambers, how in the world are flat tops gonna get you only 9.2? your calculator is wrong. Flat tops with 64cc only getting ya 10.5? man woah..

Stay with the flat tops, you'll be able to run 93 octane.

iron heads dont dissipate heat very well, so like a diesel the gas will start exploding from sheer compression, as most of the heat is already there. The higher the octane the higher the temp has to be for the gas to explode. Simple stuff here.

10.5 is not 93 octane friendly without adjusting timing to where you actually loose performance.

with most flat tops you'll get 9.5-9.7cr, this is 93 octane friendly and actually can be 89 friendly, cercumstances depend.

Your cam also has alot todo with it, this theoretical compression can be attained if there is no overlap, well guess what, most cams have some and larger cams have alot more, making for less dynamic compression.

I'd go flat tops, but thats just my .02

 

ok thanks man i really appreciate it!