I need to change gears in the chunk.

My 69 chevelle nomad has a 700 R4 overdrive, and I can't really use overdrive under 70 mph. Also, the current gears are horrible for towing. I don't have a tach, sorry.

A quick conversation today yielded that "most" guys whom upgrade to a 700 R4 go with a 3.73

I'm getting new wheels, to eliminate the rub issue on the rear. The new wheels will be 8" rims all around. This will allow me to rotate tires front to back, and I can also drop the lift, improving pinion angle. Also, it means the tire diameter will be about 26". ( I lifted it because of wheel rub )

To get new gears, I must identify the rear end. It's the number of bolts on the gear carrier, right? While I have the cover off, I could also count teeth I suppose, to determine exactly what I have now.

So: recommendations on new gears, and is there anything else I need to find out to order them?