I have a 88 formula ws-6 which to my understanding had drums on the back from factory even though it was a ws-6. My car has rear disks so am I wrong and did the ws-6 come with rear disk or did someone do a conversion?

 

Likely the car came equipped with discs--the IROC, for example, could be equipped either way.

JamesC

 

The WS6 option didn't necessarily include the rear disc brakes. Some years it did, 1988 it did not... but it was a separate option available if the car had WS6.

 

So it is possible it came out of the factory with the disks on the back.

 

yes

 

Does anyone know what size rotor pontiac would put on the back in the factory just so I can hopefully tell if they came from the factory or not? Is there any better way of figuring out what size/type of brake it is so I can order new rotors and pads if I need to?

 

Check for single-piston Delco-Moraine iron calipers with 10.5" rotors on all four-corners (non-performance package).

JamesC