LT1's should be flat top pistons also. 1992 - 1997 B and F cars. Have to make sure it is the 5.7 in the B cars. Some of them had the 4.3L "Baby LT1". I have built engines with used pistons but if I am that far into it, I now would rather go new, especially if I am having to install pistons on the rods with press fit wrist pins.