If you know how to port a head, these may… MAY be a good head to use. If you don’t know how to port and you do not want to pay big bucks for a head porter, then the best cylinder head I can think of are the Trick Flow heads capable of helping you to screw together an engine to clear into the upper 400’s or mid 500hp area with the correct parts.
I still think the Edelbrock is a good head for mid 400 hp OOTB as cast. The thread starter could use OOTB as cast Edelbrock heads to obtain an easy 450hp. It would take a mild cam to do so and it would not be to big as to cruise the Blvd. or Hwy. Heck, copy the Blue Print engine cam.
241/247 @050. BAMM-435 hp