So I understand for the 91-92 16 inch wheels you can fit the front C5 brakes with a small amount of grinding. Correct me if I am wrong but the main difference between the C5 and the LS1 caliper are the cooling fins, so could I take my LS1 calipers, bolt them up to the C5 brackets and stick them under my factory 16s with the C5 13 inch rotors?

 

I doubt it. You'd still be moving the caliper out (away from the center of the hub) a half inch. There isnt a half inch of fins difference between the calipers.

 

So is the main problem with the 13 inch setup isnt the outer diameter of the caliper but the caliper running into the spokes of the wheels??