400 block

The 915 heads are the best BB wedge head not counting the MW. make sure if you use them to talk to whoever you buy the pistons from, you would want a flat top piston zero decked, then it depends on your stroke and what your using it for race gas or pump to figure out if the pistons will need a dish etc.. i took off the 906 and put on a set of small exh valve 915's on my stock bottom end 383 and it really woke it up. my heads came in right at 80cc if i remember correctly.