Which castings are better for 400-500hp 454 cid big block- 781 or 063 heads. i know that 781´s are open 114cc and 063´s are closed chamber 101cc heads.
thanks

 

The 781's and the 049's seem to be a popular choice for the hp you are looking for.

 

The 781 has better flow between those 2. It will also work better on pump gas because of the chamber shape.

With 2.19" and 1.88" valves, and a normal bowl port, they'll feed about any street 454 well.

 

The open chamber heads for a BBC are always better. It allows for bigger valves and they won't be shrouded. You adjust the compression ratio with a dome piston. Unlike the SBC, a BBC has a different combustion chamber shape and valve design so a dome piston doesn't hurt it.

I was running 781 castings before I upgraded. Bigger valves, upgraded valve train, port work and they work fine. When I punched a hole through one when I dropped a valve, I picked up a set of Merlin heads instead of reworking another 781 casting. I now have a small set of Canfield aluminum heads. They're only 310cc intakes. My engine could benefit with a set of 345cc heads.