Quote Originally Posted by MI2600
There is no problem with using heads with steam holes on a 350.

The 400 factory heads will have about 76cc chambers, because most of the original 400s had lower compression with dished pistons. With a flattop 350 piston, you might make about 9:1, if you zero deck the block and take a little off the heads.
The only problem with 400 heads is they will crack right at the steam holes.