Another 273 question

The problem is you can't make a 2bbl 273 into a Commando with just top end work. You don't have the high compression ratio pistons. So you wind up with long duration and no squish — that's not how to make power. You'd be better off going the other way, with an RV type cam to try to make some torque, with that heavy wagon. You might have room for a tall intake, if you could find one.