Newb question... have a 8 3/4 rear end came stock on 69 polara 383, are all 8 3/4's sure grip? or do I have to go find one or get it rebuilt?? Thanks.

 

http://www.justdifferentials.com/ind...oducts_id=1599

Any thoughts?

 

If I am not mistaken, sure grip refers to the center section, and not all 8 3/4's are sure grips. Some had open differentials. You can test this some how...but I have been in drag racing too long, where everything has a spool. Some one will correct me but I think if you spin one wheel if the other turns in the opposite direction, it is a sure grip. "He said crossing his fingers, and hoping he is right!"

 

No. All 8 3/4's are not sure grip.

 

Sorry, a sure-grip or "posi" will turn both wheels in the SAME direction. An open rear end will turn them in opposite directions

 

The cool part about an 8 3/4, is that if you can find a Sure Grip center section.... it's a fairly simple task to swap them out. I did this once and bought a complete rear end from a '68 Roadrunner to put in my first C body.... Wrong! Had it all cleaned and painted up but, I hadn't measured the overall length and the C body axles are longer. So, I ended up swapping the 3rd member and everything worked great.

 

Seen plenty of 8 3/4 with opens.

A, B, C, E and truck 8 3/4s are all different lengths. A bodies have the shortest.