HELP NEEDED Identifying Brake Spindle - likely from a late 70s Volare

So, what brake calipers would fit a FMJ spindle???
We've tried the supposed single piston replacements, and they don't seem to fit correctly.
(I had ground those off to clear the wheel edges - had also already bought 14 inch tires!!!)

Anybody know anything about an "Optional Mounting Adapter"????

*sighs deeply*

hold on...

(thought i was going to have to get some more parts to take pics of)

the single piston sliding caliper like you currently have fits the FMJ spindle.

the caliper bracket isn't "optional". it mounts the caliper. they only came in two sizes, one for the 10.95" (usually called 11") disc and one for the 11.75" disc. understand that both of these fit the same caliper and spindle-- only the disc changed.

you have the 11" discs, 14's wouldn't even be able to bolt up they'd foul on the whole assembly.

the devil is in the details here, and you may not be mounting something correctly, or you may think that it's off. have you referenced the FSM or are you going by anecdotal "expert" advice or u tube mechanics or something?

mopar used the SAME caliper and style of adapater/spindle across so, so, so many cars (and trucks!). we know that the system works. we also know that not all 14" wheels fit even the *stock* set up, so it's little wonder that you're having a problem with an aftermarket kit.