i have a 86-87 iroc stock short block im putting the engine in a 81 z the pistons are stock for 86 or 87. i dont have the oem heads. im gona buy some aftermarket heads and i dont know the cc size for the oem heads or compression ratio. so i can calculate compression ratio. what is the compression ratio and cc of the heads for a 86-87 iroc

 

stock heads are 76cc and with stock pistons, the compression ratio with .052 inch head gaskets is 7.97 to 1. ive done an entire blueprint on an engine here at school. now it was a different block (4 bolt main truck), but the pistons are the same. now, do you know if it has a one peice rear main seal? some early 86 still used the old style 2 peice, but most of them used a one peice. the change to one peice calls for a different crank and flexplate