Thread: 400 Heads

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I've got a 350 short block on the way. I've got a recently rebuilt set of 400 heads. (with the steam holes) Can I use these on the 350 block, or am I asking for overheating or cracking problems? Don't want to buy new heads if I don't have to, as these are ready to go. Thanks.

Steam holes on average don't pose a problem. The compression levels will not make you happy unless your pistons are domed and "squeezing" the gases to meet you expectations. The 400 heads do have bigger chambers and will drop C.R.

Originally Posted by tcmers

I've got a 350 short block on the way. I've got a recently rebuilt set of 400 heads. (with the steam holes) Can I use these on the 350 block, or am I asking for overheating or cracking problems? Don't want to buy new heads if I don't have to, as these are ready to go. Thanks.

I would try and find a heavier casting number to be re-built.
993,441 are both good picks.

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.

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.