Ok, that method of measuring is so f’d up. If I hold a ruler straight across the middle of the two bottom holes and then use a tape measure for the up measurement, I get the 3.5” from middle of bottom hole to that flat spot. I thought the Disc Tech article was 3.5” from hole to hole. But pic#6 is sure confirmation that my adapters have been grinded.
Okay, so whats the distance between the mounting holes on the spindle? I ask because I have a spare set of adapters for a C body that might bolt on your spindles but I don't know if they will position the caliper correctly over the rotor. If you're willing to try them and post pictures, I'm willing to send them, and maybe we all learn something.
These are what I have, they measure just a little over 3 1/2". If you think they may work for you and want to give them a try, PM me your shipping info and I'll get them sent this week.
Being a 69 it should have four piston Bendix brakes so anything about "original" is suspect....
Quoted from the O/P "The rotor is roughly 11.5” OD and is 0.75” width" I'm wondering if it's the 66-69 spindle & rotor with the 70 caliper & bracket rigged to work... Fact is I think that exactly what's going on... This is a set of 66-69 backing shields.. Which appear to match the picture posted of what's on the car...
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Yeah, the four piston stuff is intermittently available and when it is it's $$$$.... If I were you I'd consider tracking down 73-76 A body spindles, rotors & brackets... Mismatched parts might be fine but if there's a weird problem hiding in there when it pops up it could be to late.....Hmmmm, interesting stuff. Ever since I got the car the single pistons have been on and I’m guessing the single pistons are easier to find.