Question: Rear end oil:

[401KVet]

Would anyone recommend using Royal Purple full synthetic oil, 75 W 90, with the GM Additive in the rear end over the conventional oil?
1980 Corvette.

Would going with conventional oil be a better thing? Can synthetic oil cause problems in something this old?
Thanks,

 

[black_81_vette]

Cant hurt so why not?

 

[Vettehead Mikey]

There's no known advantage so why bother?