Are you saying you think you could get 650 out of an edelbrock or speedmaster? I dont want to imply its impossible I would just have to see it to believe it. The port cross section is pretty small with the pushrod still in the port.
I don’t think, I know. Horsepower in my case is measured by ET. My Indy headed 442 ran 5.98 in the 1/8 and 9.38@138 mph in the 1/4 with an 850 carb and tired springs running out of guts before 1000 feet (2880 pounds). My Edelbrock headed 408 also ran 5.98 with no 1/4 mile times but it is still pulling up top way harder than my old engine as it has a roller cam (same lift) and a 1000 cfm carb (2850). Remember my engine is a bracket combo so I could show more horsepower with a 10
inch radial tire instead of 14-32 slick. I could run a coastal track like many to get my fast number. I hear a belt drive would be worth a few horsepower as would a vacuum pump. 5/16 valves like many run, possibly a dominator carb, special ring pack, lightweight parts, etc. a radial is worth .20 as I’ve witnessed that many times. I guarantee you 650 horsepower is available if you want to spend the money.