well, i just got a 91 Camaro (had an 86 SC). The 86 had the T5 and the 91 has the 700r4 so im trying to find all the info on the auto. as i can. whats the average RPMs on the interstate, in OD? Im pushing near 3500 and i have 2.73s in the rear. I was thinking the tach might be off. Would the VSS have anything to do with this? thanks

 

3500 RPM with 2.73's? what are you driving at, @80-85 MPH? I have 3.42's and if I remember right at 70 it is @2000 RPM in O/D.

 

At 60mph, with 24" tall tires(p235/60/15), 2.73's, in OD,with the converter locked up, your tach should read 1600rpm.Those aren't 2.73's and that isn't overdrive. Sounds more like 3.73's or 4.10's in Drive.

 

could just be a messed up tach. a friend of mine bumped the needle on his doing a white face gauge install, and now it reads about half the rpm's it should.

take the tach somewhere to be re-calibrated, or get another one.

 

I drive a '91 Z28 with 245/50/16 tires and 3.23 gears. At 60 in overdrive my tach is at 1900 rpm.

 

Use this formula to figure rpm at MPH.
rear gear x 336 (locked up, 355 not locked up) x overdrive ratio (.7 for 700R4) x MPH divided by rear tire diameter.