Correct me if I am wrong, but I thought that the 6 pack motors had 4 "eyebrows" in the pistons ? As in valve reliefs. I realize that this involves popping a head off, but is this information correct ?? I am interested in this answer also. I have a 72 Sat (parts car) that came with a 440HP & 4 speed. The motor is supposed to be out of a 6 pack car. It has the 6 pack bottom end , it has the correct damper. The funny thing is , it is possible. This car was pieced togethor many years ago, with a ton of good parts, factory cassette deck, air grabber hood, front and rear spoilers , 2 72 RR grilles etc. Even came with a mint spare drivers door with a 71 6 pack RR vin attached to it .