Good Morning. We thought we better show how our stuff works so there are no misunderstandings! We use 1979 through 85 Cadillac Eldorado rear calipers and rotors. It works well, and bolts up to the stock 3 bolt housing flange.
They are a perfect hydraulic match for the stock front calipers. The rotors are 10-1/2" in diameter, so not only will they tuck inside 15" rims, they will fit inside 14" also- my 83 Berlinetta has them and they work fine.
The only non-bolt up work concerns the axle flange: the outer diameter needs to be trimmed down about 1/8" to fit inside the rotor, and new, longer studs must be installed. Also, custom e-brake cables are needed, the cables run around $65.
Our brackets are 85/pair plus shipping for TurboBuick cutomers. We are also working on a mongo setup for a 87 GN, using C5 equipment.

They are a perfect hydraulic match for the stock front calipers. The rotors are 10-1/2" in diameter, so not only will they tuck inside 15" rims, they will fit inside 14" also- my 83 Berlinetta has them and they work fine.
The only non-bolt up work concerns the axle flange: the outer diameter needs to be trimmed down about 1/8" to fit inside the rotor, and new, longer studs must be installed. Also, custom e-brake cables are needed, the cables run around $65.
Our brackets are 85/pair plus shipping for TurboBuick cutomers. We are also working on a mongo setup for a 87 GN, using C5 equipment.