I have a 91 Formula WS6. I know I have 4 wheel disc brakes. I keep seeing "if you have 1LE brakes" etc. I don't think I have 1LE brakes but Im not sure. I want to buy some slotted rotors but I don't want to get the wrong ones.
thanks

Your rears are the same as the 1LE brakes. They are the 11" rotors with the aluminum calipers made by PBR.

Look at the front rotors. If they are slightly larger than the rears, then you have the full 1LE package. If they're smaller than the rears, you have the standard brakes.

If you have your car's build sheet, look for RPO 1LE. If you have it, then ..... you have it. If you don't, then ...... you can probably figure it out.

Just as a matter of odds, it's at least 50 to 1 that they're the standard ones, and not the 1LE version; maybe higher.

So basically you are saying that I (probably) have 1/2 the 1LE braks. In other words 1LE brakes in back, and standard disc brakes in front. right?
I will check out the size tonight

Well all you have to do is standard brakes will be aluminum calipers in the back and cast iron in the front. 1LE's aluminum all around.

1LE brakes on the car. (12" dia rotor)
the standard brake held up below it. (10" dia rotor)

Thanks for the photo. Im pretty sure I have standard brakes then. Will the 1LE brakes always be slotted like that, or is that an additional option?

being that you have a formula, my money is on standard.

the 1le equiped birds are very very rare.

but to answer you question, the slotted rotors are added, not standard 1le equipment.