To put on one of many rear disk conversion kits for sale out there, does the axle flanges have to be machined so the rotors will fit? I was looking at this kit and have been emailing him with questions. He has not responded to this question though.
http://cgi.ebay.com/ebaymotors/GM-Rear-Disc-Brake-Conversion-Kit-10-or-12-Bolt-A-F-X_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1171Q7c66Q3a2Q7 c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1 Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem56 31926d11QQitemZ370198867217QQptZMotorsQ5fCarQ5fTru ckQ5fPartsQ5fAccessories

They shouldn't but the hub hole needs to be opened up a bit. I find it very amusing the lines of BS these guys advertise, most advanced...LOL.
He's buying from either MBM or Right Stuff, same kit, caddy calipers and Trans Am rotors, been around for many years. Both suppliers I mentioned above have not been opening up the hub hole to clear the axle flange hub. I think many folks have been opening it up with a die grined to fit. Make certain the kit includes the parking brake cables because those calipers will not work once the pads have more than .030 clearance between them and the rotor, You must use the parking brake to enable the ratchet mechanisim in the caliper to keep the pads close to the rotor. They from 79-82 Cadillacs. I think you can also find that same kit on Ebay for a lot less then what he's advertising.

thank you very much

I'll modify one of my previous statements. The price is good when you consider "free shipping". At first I thought it was the selling price only.

Another thing to consider is if you have a 68-69 the kit will not fit with staggered shocks. Many of the guys selling this will replace with 2 left side calipers so the one side can be mounted to the front to avoid shock, this causes problems with the parking brake cable on that side, must be considerably longer, some don't tell you that and don't supply the different cable. Again, the parking brake MUST be utilized in order for the calipers to continue to function.
Otherwise a decent kit. You can install the shock relocation kit to make rear disc a simpler install.

I put a 4 disk set on my car this week - passenger side rear rotor fit without a problem; driver side rear needed some grinding. If it is not too late, ask the vendor for a caliper that has bleed valves that can be bled without removing the caliper pins. There is a new stlye out that enables easier bleed than the old style.