going from 37 to 36 is a little less than 3%. there's about a 5% difference between 19 and 20. you probably can't hit it exact but being with in 1% is pretty good for the old speedos. if folks would do the math on this stuff a lot of guess work could be tossed out. the hard ones to do are the '65 and earlier were there are only 6 pinions to choose from and there's about a 5% spread between them all.
The 35 tooth gear worked almost perfectly. It is one tenth off in 10 miles, so 1 mile extra in a 100 miles. Got the needle set at right about 1 MPH fast at 60 MPH. It's more accurate than my all factory stock '92 truck.
Thanks again guys.
