10 years ago I did a Right Stuff 4 wheel disc brake conversion on my 1972 Cutlass S. I had to grind the outer circumference of the rear axle for the rotor to fit on the axle. I just purchased new axles and remembered my situation. The rear rotors are around 11.1" diameter rotors and the inner has to be 6.25" to fit the axle. Has anyone ran into this? The calipers are similar to old GM S10 calipers with the 2 Pins.

 

Doing a right stuff conversion right now and the front page of the instructions talks about it.
I ordered new axles from Moser and had then machine them to work with the conversion.

 

Yeah. I might have to look back on my instructions to see if they said anything. I talked with the guy I got my axles and he said he tells the guys who make the axles to modify the axles but they don't. He recommended having someone rotate them on a Jack stand while you grind it so they are more even. I might see how much my local machine shop will do them for. I just need to get all my measurements.

 

I bought the Right Stuff rear kit a few weeks ago and ran into the same issue with the axle not clearing the rotors. I called them and they told me to get them custom machined. I ended up returning it and dropping the money on a Wilwood BOP rear kit. It is nice! It has it's own drum mechanism that bolts on for the parking brake. The whole thing look less than an hour to install and fit perfect. Made specifically for the BOP setup. I just had to cut off the bearing retainer and use the one they include in the kit. I also took the instructions recommendation and drilled out the studs for 1/2" studs. I have custom wheels on my car and it looks great.

This is the kit I got https://www.summitracing.com/parts/wil-140-13513