im looking into rebuilding my rearend in my bird.... the right way with a posi unit and a set of 3:73 gears. right now it has 3:42 gears. what do i have to do to my speedo to correct it when i put the 3:73 gears in?

 

doesnt anyone know?

 

Sure I do but I dont think your going to be very happy with the 3.73's. I had them in my Camaro and I sucked the gas like no other. But if you want a killer off the line then you will need a 15 tooth drive gear "grey" and a 41 tooth driven gear "purple I think." Ot what they hey just go here http://www.700r4.com/SpeedOCalc/