A hi-compression LA318 or a regular Magnum 5.2 come out of the gate at about the same power as a hopped up 4bbl Commando 235hp, but has the added advantage of a boatload more torque throughout the rpm band, allowing you to run a rear gear that is a one or even two sizes smaller.
And even a low-compression 360-2bbl annihilates them both, with the advantage of running even less rear gear.
Depending on the direction of your project, a 5.2/5.9 Magnum with an A500/518overdrive and 4.30s to 3.91s is gonna be a dynomite combo. The od ratio is .69, so even say 4.10s, are the equivalent of 2.83 cruising gear, so 65= about 2250rpm,
and the starter can be 2.74x3.91=10.71 with the 904based unit; or 2.45x4.30=10.54 with the 727 based unit.
With that much Torque Multiplication, you don't need a lot of power in a streeter, and you can run the factory TC.
The nice thing about these steep street gears is the shifts come early and closer together. Second with the either combo is gonna get you 60mph@~4900/5000 just as the cam is done, so perfect; the engine has run thru the power-peak twice on the way to the speed limit. Put some power in the heads and yur done.
But HO273S or HO273ST (Hi-Output;supercharged or Staged Turbos) has a nice ring to it. All that lil engine needs is some form of supercharging, and then you can run something like 2.94 rear gears for 65=2400. Ima thinking staged turbos; 400 on turbos should be easy on the mini-Mopar;
but a belt-driven side-mount is probably easier and cheaper.
