The 340f go for about 200$ in the junk yards here in Portland. Check car-parts.com. Look for one out of a 95+ 4runner as these are the most common. The Inchworm adapter bolts strait up to the factory tailhousing and is around 400$. The only down side is you need a 23 spline front case but if you only run one case with 4.7 it won't matter cost wise. A single 4.7 case should be plenty low enough with the auto but it might suck losing the stock low range for higher speed stuff.
340f with inchworm adapter to gear driven case. The tranny is from a tundra but they are all pretty much the same.
