My 71 has an open diff, I want to convert it to a limited slip and change the gear ratio. The car is going to be a street car, no strip. What brands are good and where is a good place to get them? At what point do I need to worry about upgrading the axles?

 

Detroit Trutrac
https://www.summitracing.com/parts/d...a556/overview/

 

With my 8.5 differential I had a 3.23 and the Eaton Posi. Pretty good. West coast differential.

 

Monzaz or 507olds should be able to hook you up. They are both active on this site.

 

Need to really figure out what your going t do with the car for ratio. Most all Posi units will be fine for street operation.

Transmission kind, how built the engine is ...as too big of cam and low compression will need more gearing as it kills low end power at lower RPM range. and where your doing most of your driving...freeway light to light action just cruise etc.

Jim
J D