just incase anyone else was interested in the rpm running these gears then i found answer in another fourm.want to share answer with everyone on here.
gearhead1011 wrote:
I think the 700r4 has .7 overdirve. If that's right with a 2.38 rear it would be turning about 1700 at 70 mph with a 25" tire. That would go to about 2,650 with a 3.73 and 2,775 with a 3.90.