I am working on a 1987 Firebird for my GF's little brother, built a pretty stout 4 bolt 350 with good heads and such, stout 700R4 with convertor..but it still currently has the stock rear. I think I found a disc brake posi rear, but from what I hear it is a different width. How much difference is there? Also, I put on Hedman shorties and don't have a starter yet, but I did trial fit an early starter and it bumped the header tube. Do the later cars use a smaller starter?

 

No, to the rear width question. No, to the starter question. With headers, you may require a Mini-starter.

 

But don't the GTA's and such use a different offset wheel because of the rear? As far as starter, are you talking about an aftermarket mini starter? Any recommendations?

 

The off set of the wheel has nothing to do with the standard rear axle width. When you install headers it took away clearance for the stock starter. A aftermarket Mini-starter will sometimes be required. Just remember the headers may give any starter a problem with Heat Soak.