Speedo Broke

I picked up a 91 Z28, not sure of the gear ratio. it has the 700r4 OD trans with a 5.7. My question is... what speed am I going at 3250 rpms and 2750 rpms. If you dont know those specific rpms let me know what you do know. also If any of you are still driving your cars this time of year I can wait a day or two until you drive you car and see for sure. Thanks

[WMCCjames]

Without knowing your rear gear ratio and your speed you cannot figure it out. You are missing two many parts of the equation. Just time yourself between mile markers and you will know what speed your going and then you can figure out your rear gear. OR, pull the cover off the rear and count the teeth on the ring gear and the pinion. You will aslo want to know what your tire size is to be as accurate as possible.

[thursday12889]

since were on this subject, i put my burnout tires on the s-10 today and there smaller than stock, not much, but being smaller (correct me if I'm wrong) wouldn't my speedometer actaully read faster than what i'm really going? Or would it be the other way around?

[sping012]

Correct, the smaller diameter of a smaller tire then the stock size tire will cause the speedometer to read faster than your actual speed, and should also put up the odometer at a slightly higher rate.