Ah, that's cool. Doin' the good work.

As for gears, I've been running a 6.2 chevy for a while with stock gearing, and it lived just fine until I lost that dag-blasted oil cooler hose. But it never saw higher than about 55 mph indicated with 38" tires. When I scrounge enough extra change, I'll be going for a set of 4.56's in the stock axles. Hopefully an overdrive tranny, too. A lot of folks will tell you not to waste your money, and go with a modern dana 60 and 14 bolt, but that's a pretty big initial investment. Although now that I think about it, I did twist a tranny in half with a 7.3TD once. Maybe the modern stuff would be better in your case. Just depends on how much money and time you want to throw at it.