The 3.9 is a good all-around final drive ratio for the Vintage racer. These are semi-helical for maximum strength and superbly manufactured by Quaife, one of the UK's leading transmission manufacturers. Tooth count is 55 and 14. They are available to fit standard or LSD-type differentials.
For Tran X, & Salsbury Differentials with Ring Type Crownwheels please select LSD.
For use with ATB and Cross Pin Differential please select STD.