Can you run a turbo in that class? Blow through an A2W intercooler into a carb box?
It would definitely kill the problem of parasitic loss, and with that motor you could
use a small, self contained unit without having to mess with oil lines or external
wastegates.
If not, I'll agree with the other guys- an Eaton or other S/C with a smaller ratio;
you may gain HP with the 3-71, but you're losing a large amount in driving it. A
more efficient unit won't look as cool, but going faster is cool, too