How do i change the 3.9 ratio MGB rear end to a 3.07.I have a 78 MGB with a Rover V8 and 5 speed.I bought an MGC 3.07 pumpkin to install.Any info will be appreciated.Thanks.Les.W4MGB
If I recall correctly you have to machine .215 off MGB case for 3.07 gear to fit or use the MGC case?
You can simply install the MGC differential complete...much easier than installing the MGC C&P into the MGB casing.
Be aware that the MGC differential most likely came from a wire-wheeled car (if sourced in the States) and will be narrower than your current MGB differential (assuming that you have a steel wheeled MGB)
Have you verified that the MGC differential is indeed a 3.07. They were available in 3.07, 3.7, and 3.31 gearsets.
There should be a stamping on the case...the gears are stamped as well.
DifferentialCaseGearsetMarking.jpg
Gearsetmarkings.jpg
The numbers are 501 14 43.Thanks.Les.
43/14 = 3.07