[Volfandt]

I just recently went through and replaced most of the brake system on a 49 GMC someone else had built many moons ago. I spent more time researching the components than actually doing the repairs. If the builder made notes I didn't get them....
The comment about GM providing the basis for most of the calipers for these aftermarket kits definitely rings true in my case.

I used calipers spec'ed for a 79 C10 as well as the flex lines and they bolted right up.
Only thing is, to keep the bleeders on the top side when mounted, the calipers had to be swapped, i.e. the "R" labeled caliper is mounted on the left and the "L" labeled caliper is mounted on the right.
They work pretty good considering they're controlled by a firewall mounted 75 Pinto dual diaphragm power booster, master cyl and combo valve......

Johnny Cash would be proud LOL.