Alberts84

hey there everyone i have i a quick question lol, ive come across a motor that i guy at work is selling, its a 355 but right now it has .100 domed pistons and 64cc chevy bowtie phase II heads right now the motor is around 11.5 - 12 : 1 compression which is way to much for the street, i was wondering if switching the pistons out for some flat tops would reduce the compression enough for pump gas use, another option is that he has some gm 76cc heads that have were ported and were on the motor before this rebuild would switching the heads instead of the pistons work which do you think would be the better and more hp producing course of action any input is welcome
thanks

F-BIRD'88

You could employ either of those choices to get the cr down to what will work on pump gas. If you want the most power then keep the bowtie heads and swap in new flat top pistons. If the cylinder bore are worn you'd want to bore and hone to the next oversize. If the cylinders are ok just ball hone and install new pistons of the same size and go.

Many bowtie heads are used in racing and have been milled to reduce the chamber size (increase compression). i would cc the heads to deturmine the actual chamber size and then select the right piston ( dished or flat top) to get a manageable cr.