wanted: 3:08 truck diff and or gear set for 67-72 truck
beaumontguru said
Mar 4, 2017
Just in case anyone might have a gearset or compete diff for a 67-72 truck with factory 3:07 or 3:08 gears. Looking to convert my 3:73 to a better hwy gear. Not sure if the later 70's trucks are the same carrier or not, also not sure if the carriers are the same from a 3:73 to a 3:08? Even the truck forums provide conflicting views. 1/2 ton stuff. locally prefered.
4SPEED427 said
Mar 10, 2017
Dave, we're back now from a week away. If you can answer a couple of questions I might be able to help you with this.
12 bolt?
Leaf or coil spring rearend?
beaumontguru said
Mar 10, 2017
Its a standard 1/2 ton diff with coil springs, Yes is has a 12 bolt cover plate, but its not the same 12 bolt as a car.
They were common on most 69-72 trucks with 350 engines and/or automatic trans.
4SPEED427 said
Mar 11, 2017
GM parts book says 67-74 ( I didn't check the 74 and up parts book) carrier # 6258088 interchanges IF you have 3.07 or 3.40 ratio. It also says carrier # 3938932 fits 3.73 or 4.10 ratio. From that I am sure it's safe to say that you have to swap carriers to put in 3.07 gears.
I am betting the carrier fits right up until they went to the 8.5" which I think was 1981?
beaumontguru said
Mar 11, 2017
Cool thanks so much for confirming this! I was speculating that i might have to change carriers, but miss-information on the internet gave conflicting results. It would be nice to just find a complete drum to drum setup
4SPEED427 said
Mar 11, 2017
The one thing I didn't check and I may still some time today is the side gears. I'm not certain that they all have the same number of splines on the axle. I know on the 8.5" there was a spline count change during production and you can't interchange the complete carrier because the axles won't slide in.
Just in case anyone might have a gearset or compete diff for a 67-72 truck with factory 3:07 or 3:08 gears. Looking to convert my 3:73 to a better hwy gear. Not sure if the later 70's trucks are the same carrier or not, also not sure if the carriers are the same from a 3:73 to a 3:08? Even the truck forums provide conflicting views. 1/2 ton stuff. locally prefered.
12 bolt?
Leaf or coil spring rearend?
Its a standard 1/2 ton diff with coil springs, Yes is has a 12 bolt cover plate, but its not the same 12 bolt as a car.
They were common on most 69-72 trucks with 350 engines and/or automatic trans.
I am betting the carrier fits right up until they went to the 8.5" which I think was 1981?
Cool thanks so much for confirming this! I was speculating that i might have to change carriers, but miss-information on the internet gave conflicting results. It would be nice to just find a complete drum to drum setup