Building out a 273 recommendations

Like was said - concentrate elsewhere unless the drivetrain is coming out for a full resto deal. Keep the cam smaller. Under 220° @ .050 and i always liked the sound of a solid flat tappet cam... Add a decent exhaust which on that car means a well build Y pipe, and something like 2 1/4 or 2 1/2" pipe to the back with a decent muffler on it. I'm not a fan of duals on these cars but that's another choice. Gearing you're fine. Transmission you're fine assuming this is a cruiser car and not a racer.