VCCA Home Forums TECHNICAL - 1945 AND NEWER 1955-1957 1957 REAR END RATIO

i took the rear end out of the 57 chev i have, it was a ohio drag car, just doing a quick look at it bolts have been off and on i can tell, i marked the brake drum and the u joint spot drum turns 8 times to one turn of the drive shaft hook up any ideas of a ratio, i know it has numbers on the case but how can i be sure the inner unit is what the numbers say and not been changed to a "posi unit" or something, the car was a auto trans and the frame was butchered for a big block, and i mean butchered i have a new frame ready to go thanks k

remove differential housing from axle housing. various #'s will be stamped on the ring gear, such as 39/10(which is a 3.90:1 ratio rear) or 41/9(which is a 4.56:1 ratio). if its a posi-carrier, the spider gears will be "hidden" by the clutch pak assembly. you really can't trust the cast #'s or stamped #'s on the differential housing as the drag strip boys have probably modified the differntial housing in the past.if thewre are no #'s stamped on the ring gear, simple count the # of teeth on the ring gear and the # of teeth on the pinion gear, divide pinion into ring #'s and you've got the ratio of the rear end. mike

thanks mike

3.36