Seven mains came with the later series sixes. I don't know if there was ever a custom block or a girdle setup.
There were 4 different GMC heads. They will all fit all blocks. Two had large intake ports and are the choice of most racers. The 270H head has a domed chamber and works with pop up pistons, The 302 head has a D shaped chamber and uses a flat top piston. Lots of work has been done on each type. You'll have to figure which fits your build.
Last edited by Beater of the Pack; 07/11/21 12:58 AM.
