1970 Duster, Trans-Am-inspired "Pro Touring" build

That’s because only the shorter A/E and earlier B-body spindles are reproduced. The taller 73+ B/R and FMJ spindles are not reproduced, so the replacement spindles are listed for everything.

The caliper brackets for the single piston calipers are the same for each style, and can be used on any of the spindles that came with single piston calipers, so, ‘70-‘72 B/E, ‘73-‘76 A, and ‘73+ B/R/F/M/J (the taller ones). That’s true for both the 10.95” and 11.75” brackets, pin and slider style. Some of the calipers can’t be interchanged, like the 73+ B calipers are a bad choice for A-body conversions because of the brake hose location.

That doesn’t necessarily apply to aftermarket brakes though, because the taller spindle may change the ball joint/ UCA clearance to a larger aftermarket caliper. I would imagine Vlad would take that into account so only one style of bracket is necessary for both spindles because that would be easier for production, but that might not be the case if he only had one style of spindle to work with.