tt is 4.10, open is 3.90. All you need to do is swap the differential itself, the axles are the same on both units. for instance I have been using '49 axles for 10 years with a '57 3.90 differential. I do use an overdrive with this giving me a final drive of 2.73; that is .70 X 3.90 = 2.73


~ Cosmo
1949 Chevy Half Ton
Rocinante, like Don Quixote, he is awkward, past his prime, and engaged in a task beyond his capacities.
"...my good horse Rocinante, mine eternal and inseparable companion in all my journeys and courses." ...Don Quixote, Cervantes
"If you come to a fork in the road, take it."...Yogi Berra
"Rudeness is the weak man's imitation of strength." ...Eric Hoffer