head bolt bulge in runner?

do 915s have the head bolt bulge in them like the 596s. Also do 596s have the same potential as the 915s and any other
small block heads.

I haven't done any porting on my heads a shop in andover did them about 2 years ago just so everybody knows. and I just flowed the way they did and now I'am going for a more fully ported form.