Highest flowing sbm heads?

fishmens67 said
400 block and 3.75 crank for 451 cubes.
The 451 is the most reliable Chrysler stroker, with an Indy head can make 600 reliable HP jumping off a log.

IF the 400 could make 600 hp as cheap and reliable as the 6.4 would be a good discussion, but I thought this thread was about small blocks.