Finding 3.91 gears???

[Capt. Slapshot]

How does one find a new set of 3.91 gears? I'm restoring my Boss 351 & all I can find are 3.89 & 4.00 gears from pretty much everyone. Any ideas??

 

[PoppyMod]

How does one find a new set of 3.91 gears? I'm restoring my Boss 351 & all I can find are 3.89 & 4.00 gears from pretty much everyone. Any ideas??

I guess I have to ask, is a 3.91 gear set factory correct?

 

[Capt. Slapshot]

I guess I have to ask, is a 3.91 gear set factory correct?

yeah, those are what they came from the factory with. they're pretty worn, I'd like to replace them with a new set of 3.91's if I could find a place that sells them

 

[PoppyMod]

yeah, those are what they came from the factory with. they're pretty worn, I'd like to replace them with a new set of 3.91's if I could find a place that sells them

Have you checked with Currie (west coast) or Perogi (NJ)? (spelling might be lame, but close)
Good Luck!

 

[jerry S]

How does one find a new set of 3.91 gears? I'm restoring my Boss 351 & all I can find are 3.89 & 4.00 gears from pretty much everyone. Any ideas??

does the car have to be concourse correct? If not, there would no discernible difference between 3.91 and 3.89.

RPMs at 60 mph would differ thusly:

3.91 pinion gear, 27 inch tire at 60 mph = 2998 rpm with three speed auto
3.89 pinion gear, 27 inch tire at 60 mph = 2982 rpm with three speed auto

Unless your car needs to be concourse correct, would you really notice the 16 rpm at 60 mph? I'm just sayin'

 

[Capt. Slapshot]

does the car have to be concourse correct? If not, there would no discernible difference between 3.91 and 3.89.

RPMs at 60 mph would differ thusly:

3.91 pinion gear, 27 inch tire at 60 mph = 2998 rpm with three speed auto
3.89 pinion gear, 27 inch tire at 60 mph = 2982 rpm with three speed auto

Unless your car needs to be concourse correct, would you really notice the 16 rpm at 60 mph? I'm just sayin'

and that is a very, very, good point