Quote Originally Posted by Bug View Post
At 70 mph with 2.41 rears he would be running about 1800 rpm and with 3.08 rears he would be around 2300 rpm if he is running a 1 to 1 final in the trans.

If it were me I would rather be around the 2300 rpm. Would not dog as bad when you stepped on the loud pedal.

My youngest son had a 81 Vette that ran around 1800 at 70 mph. It was fine but a Vette is lighter.
Thanks for the response Bug, but the 700R4 is an overdrive trans so the final drive is somewhere in the .68-.73 range I think. Thus, the lower 1385rpm at 70mph. I agree that it will probably dog quite a bit at that low rpm. He's trying to avoid messing with the rear end.

I read where an 81 Corvette can weigh in at around 3300 pounds. Usually, these old Fords are less than 3K, so 1800rpms at 70 would probably work great.