i talked to the guy at probuilt and he says later 700R4 have larger sprags and therefore are lubricated better, im wondering if you can put a later model sprag in to, say, an 84??

 

Absolutey, but you will need to swap over the whole sprag assembly and throw away the 2 thrust washers that went w/ the old sprag.

If you had a newer tranny, all you would have to replace is the sprag itself, and the new Borg Warner 29 element sprag is pretty stout. But having an old style (unless its already been replaced) you will need the whole assembly.

 

about what does that runn (cost wise) including assembly?