273 warm up!

Try to find an original AFB, otherwise have the intake bores opened up for a 500 cfm Edelbrock. Assuming you have the original solid cam setup. I'd run an Isky E-4 or call Racer Brown for an ST-1 or what ever Jim suggests. Add 340 springs and a double roller timing chain. Is it an automatic transmission? Exhaust manifolds are the same as the Commando / Charger engine. The difference was the Charger exhaust was single 2.50 pipe with 2 straight through mufflers in series. You don't need different pistons. A good quick curve electronic distributor would be good also.