59 power brake booster
The power brake booster was an easy install. Since it does shift backwards, I believe you drill one hole in the frame for a mounting bolt of sorts... The instructions from Classic Performance pretty much lead you through it. I plan on doing all my brake bleeding prior to putting sheet metal back on the frame and I think the filler hole in the floor may need to be moved slightly... also added residual valves since it is mounted on the frame.
If you goto Classic Performance site, I think you can download the install instructions to get a good idea of the install.
The 48 is bone stock. Got it off ebay also... its from S. Dakota... I use it as incentive to get the 59 on the road!