The stock iron heads do not really hang over the block deck surfaces at all, except for the accessory bosses that stick out a bit from the rest of the head casting and the deck.


I think part of the reason why the Edelbrock heads are cast "wider" and hang out over the block deck surface is that they made the ends of the heads flat where the accessory bosses would have been compared to iron heads, instead being only threaded holes in the overly-thick ends of the heads. It is stronger to thread into a flat end of a large aluminum casting than a small boss that sticks up. The Procomp heads are pretty much a copy of the Edelbrocks from what I have seen/read.

The cast aluminum aftermarket heads for Olds engines will work fine with a Big Block and a mechanical fuel pump without any mods.

Hope this helps!

You can’t use aluminum heads at all on a small block with a mechanical pump. You can’t grind enough away before you hit water.

Thanks for coming in to correct that Mark, I removed my incorrect info about small blocks.

You hit water though right? So I was right.

Sure.