Street\Strip 408..Boiling it all down

All aftermarket heads as boxed from the manufacturer have issues. They are assembly line machined and assembled. So defects are common. Edelbrocks suffer most from too-tight guides. I've also seen seats out of round, a completely wrong spring in a Pontiac head, and the surface for the head gasket is good for some gaskets, not smooth enough for Cometics. Chamber sizes are usually good. So all heads should be checked by a good head shop. The springs they include are general purpose single with dampners. The modern fast rate cams of any size will require new springs, and care needs to be taken to make sure the retainers will work with your choice of spring.

The oil system mods can be found in any number of books on building small block mopars. Szylagi's is easy to find and I believe it has it in there. It's enlarging the oil passages from the lifter galley to each main saddle from stock to 9/32. I actually go to 5/16 because that's the size of the feed hole in the upper bearing shell.