Dr diff spindles

I'm sure Cass (DoctorDiff) will chime in after the holidays, but if I remember correctly the reproduction spindles are the same height as the factory 73-76 A-body spindles, not taller like the later FMJ spindles were.

As for the original debate, it was Richard Ehrenberg's fault. In his original "Disc-O-Tech" article he made the claim, without any evidence whatsoever, that using the FMJ spindle for your BBP brake swap would cause all kinds of catastrophe and suspension geometry problems, over-angling of ball joints, terrible bump steer, cats and dog living together.

But here's the deal- he's full of crap. He never posted any geometry numbers to back up this assertions. He never tested bump steer numbers, or looked at camber gain, or even bothered to check if the ball joints were somehow going to have some kind of interference or wear issues. He never bothered, and based on his total lack of evidence I can only assume that everything he said was just speculation on his part.

The article you linked, from Mopar Muscle, actually did all of that. And you see the results. There is a slight change in the bump steer geometry. There is also an improvement in the camber gain. And the ball joint over angling thing is complete BS.

The bottom line is, for most applications most drivers will never notice the difference. It's barely worth a discussion, the changes are so minor. Cruising around town you'd notice nothing at all. I run FMJ spindles on my Challenger and my Duster because of the improved camber gain, because I do run wider tires up front (275's) and the camber gain is more important. But I'm not going to BS you and tell you I noticed the difference when I switched from stock '74 A-body disk spindles to FMJ's, because I didn't.

And yeah, I'm almost positive the reproduction spindles are the factory A-body height, not the FMJ height anyway.