What camshaft spec for 425 hp

They'll take a 150 shot. As long as you don't lean it out.
Really, I did not know that, I was told that a 75 shot is all I can use with stock pistons. That’s good to know. Maybe I’ll be a little conservative and put 100 shot on it. I did that with a mild 8.5 compression 350 in my old 1971 Camaro I used to have and it Picked up 11 miles an hour and drop a full second on ET, just from 100 shot.