65coupe88hatch

whats the stock size gear for the speedometer on an 86Gt. my speedometer is off by 20 mph and i have to get it fixed before i get a ticket or something.

AdderMk2

you need to find out what you have, not what is stock..

because you are assuming that your car IS stock...

jack up the back of the car, mark your driveshaft and spin one of the rear tires one full turn. count the number of times the driveshaft goes around and LUK... we can go from there

mjr46

20mph high or low reading off??

65coupe88hatch

its 20 high

mjr46

then the rear may have gears, you need to find out what ratio is installed and if that requires removing cover for accuracy to count teeth on ring and pinion then I'd do it for accuracy

65coupe88hatch

after you counted the teeth how would you find out what speedo gear is needed

mjr46

take the teeth on the ring gear and divide by teeth on pinion and depending on ratio there are specified speedo drive gears post ratio and we can direct you in correct purchase