[chris mc bride]

Will have to dbl check but think my 69 panel with factory 3 on tree has a 3.08 gear. Mileage not terrible and that's with 454 and medium cam.Heck it isa better than my 2016 Silverado 2500.

I have a 4l60e ready to go in but need standalone computer to make it work. When it goes in 3.73 or 3.90;s are going in rear along with posi unit. Better milage and tire frying first and second and maybe 3rd.LOL

If original is not issue I would go with over drive transmission. There is reason late model stuff has 6 and 8 speed transmissions. I 700r4 had a over drive of .75:1 so 25% reduction right there.