I'd look at a custom Racer Brown solid flat tappet cam. That kind of power can be made with stock 2 barrel pistons, factory Commando intake and carb, and an Isky E-4 cam. Nothing to go wrong with a solid flat tappet cam, adjust the valves every 100,000 miles once broke in.
Thanks 66fs, l’d prefer a flat tappet solid stick but there’s been a spate of cam & lifter failures in the past few years. I’ve never wiped a cam before, and would prefer it to stay that way.
Ideally l’d like to build a mild 300 hp 273 that runs nice on the street with a 4-speed and 3.23 gears.