I ordered my UB Machine arms about a month ago, make sure to ask for Randy, he knows everything about the 12" brake swap for G-Bodies. It cost me ~$168 with the small Chrysler screw-in ball joints and Teflon bushings. The part number was 19-0739-4.5 the "19-" is the Chrysler BJ. The mount for the ball-joint needs to be bent 10 degrees, to have it bent, the Chrysler BJ is the only one that UB can use with the mount bent 10 degrees.
To use the Chrysler BJ, the spindle MUST be reamed to fit that style of BJ. To be absolutely sure that it was going to be 100% correct, I paid another $25 to ship my spindles (without the rotors, duh!) to UB Machine to have them ream them... I think to have them reamed will cost ~$30.
I picked the Teflon bushing because metal-on-metal, with no bushing at all seems like a not-so-great idea. I'm slightly worried about the Teflon melting by the down pipe on the passenger side, but Randy told me it is supposed to withstand somewhere around 500F, I'm going to make some sort of heat shield from aluminum.
I paid $60 for my spindles, which I removed from a 1982 Cadillac Deville (bring a BJ separator!). I paid $200 (AutoZone) for Aimco Extreme cross-drilled and slotted rotors for a 1LE Camaro (I picked 1988). In addition to new rotors, I picked up new LOADED high-end calipers for $90 from AutoZone.
I got most of my information from:
http://www.montecarloss.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=18;t=001984;p=1
The MC guys know their suspension, especially Jeff Davidson; he's a suspension genius! His site is
http://jeffd.50megs.com (I think)
When I get everything from UB, which I should have by the end of this month, I'll tell you how it all works out. The reason it's taking so long to have mine built is because I asked for the mount to be bent 10 degrees and the Teflon bushings.
Overall, I expect the whole 12" setup to cost around $600, including all the brake hardware and shipping.
I'm sure if I knew of a local machine shop that I trusted to ream my spindles for the Chrysler BJ I would be able to save at least $50 in shipping charges, another area that would save some money is if you didn't buy the cross-drilled/slotted rotors.
If you decided to use the calipers from the junkyard car, and went with cheaper rotors ($70 each), you could save even more money, or even have the junkyard rotors drilled by a machine shop. Personally, brakes are an area where I'm willing to pay more. It's cheap insurance against an accident that might be caused from using junkyard calipers, that and the cross-drilled/slotted rotors aren't going to fade and warp as easily.
Also, you could save a little money by not getting the Teflon bushings.
Though I didn't really help you answer YOUR question... hopefully I've helped others with their brake upgrade.
BTW: Has anyone upgraded from the smaller diameter master cylinder to the larger B-body one? How big of a difference does this make in braking?