wow, what a coincidence, I just logged on for the same question. I think there more important question is, where to get the RIGHT kit! just swapped a oem 4 piston on my '67 (which had a recent rebuild) only to have brake fluid gush out of a piston. I just bought a rebuild kit from National Parts Depot today, however, I got home only to find the pistons in this kit were about .25" smaller, I was pissed. I have read some opposing info on these calipers. I've read that some camaro's and Novas, etc had these too, but the pistons were smaller, 1-7/8. I measured mine and the outside of the piston is 1.675" and the bore/inside is 2.065". again the NPD kit was way too small. I saw a listing in year one for just the seals, no pistons, but that notes for 4-piston w/2-5/16" pistons, which would be way too big. I called a brake guy and all the pn he had were discontinued. so again it comes down to who has the right kit. strange thing was, the seals seemed brand new in mine and the bore was smooth as can be with a tight seal, I don't know why mine is leaking, I wondered if the piston could have bee pushed too far back when I installed it. btw lonestar caliper has the seals too but didn't tell me a pn or any dealers to go through. anyone who has the scoop on this, I'm sure we'd both appreciate it.