I had a local shop take my 69' 350 block with 3947041 heads and build it into a 383, after over a year of detonation, oil leaks, and repeated problems, This shop replaced my heads (without informing me) with 3998993's. I know that the 041's are a more desirable head, and this shop is now telling me that the crate engine heads are every bit as good as the 041's. I know that the 041's are a 64cc chamber and the crate heads are a 74 or 75cc head, which leads me to believe that he used the wrong pistons to start with. Which is the better head? and why?  

You kind of have a choice of poisons. The 041 would clearly be the better and more efficient power producer. But you have two problems; first the pistons aren't right they feature too much compression with that head. A "D" dish with a volume to put the compression from 9 or 9.5 to 1 would have been correct for premium fuel. Second, these heads do not have hardened valve seats and won't care for un-leaded fuels.

The 993 is an open chamber SMOG head, it's been around a long time and doesn't have much of a reputation for performance or efficiency. It's also crack prone, so keep from overheating the engine. On the good side, it does have hardened valve seats and will put up with unleaded fuels.

One has to wonder why he didn't use Vortecs, not very expensive and really pump the ponies with good breathing and an efficient modern combustion chamber. They're pretty much a 40 horse bolt on over the 993.

Bogie  

new bowtie vortecs,even better,and dirt cheap