Disc brake conversion (70 Dart)

Actually you are quoting yourself and them trying to back up what you posted with misinformation that you quoted as fact. Something you do an awful lot... You also don't read very well when it comes to trying to understand something. And now you claim to be a physicist, mechanical engineer and a finite element engineer. 72 *b+l -u (N)b ^l -u Not Albert Einstein or Stephen Hawkings talking Wheelchair could teach you anything.

The disadvantage in our old Mopar calipers comes from what area of the pad that can be reliably used to to calculate the braking force with focus placed on overall function of the mechanical components and factoring in the inherent design flaws. It's not just 24% more piston area. You would never really understand why a lot of multi piston calipers have different diameter pistons in them or why manufacturers choose to use sequential piston sizes in the same caliper. (Psssst it's just another way to combat uneven pad wear and promote uniform clamping force ).

If the OP wants to just upgrade to disc brakes on the cheap he could just rebuild the old Mopar ones and it will work. That might be all he really needs for HIS car. But if a guy wants to buy a Willwood setup that will work better. He's not just a "check writer", like you say. . He might actually need better more reliable braking. Maybe he just wants to upgrade his car to maxim performance potential in certain areas of his own car. And we don't need your analysis on you being right Dr. 72bluNblu PhD.

Your own car doesn't need SPC uppers, Howe racing ball joints, QA1 Lowers, Hellwig sway bars, Caltrac sliders, incorrectly welded in sub frame connectors or even 275 & 295 width tires on 18" rims to drive around on the street. That said, you don't even need your Cobra calipers on 13" rotors ... You don't race it you've stated many times over. You claim to drive like your grandma in it everywhere, which explains how you get 60k miles on a set of brake pads? (Dude, you might want to change them out more often than that. Pad materials do deteriorate from the metal backer plates). You really only need a Slant 6, 4 wheel drum brake car.

For a guy with a 500 hp brake dyno, you seem to be short on data. You don't need to calculate anything, put a '73+ mopar caliper on your dyno and give us the numbers. Heck, put a Wilwood Dynalite caliper on there next and completely settle this. Should be pretty easy for a guy with a brake dyno to get all the information we need.

The last time I tried to put a 14" Rally wheel on a Wilwood, it wouldn't mount on the studs cuz the caliper is way too big, and in the way. Same with a regular 15" wheel. I hope someone can shed some light on that.
The price of the brakes is high, but to then find your favorite wheels don't fit, could be annoying and costly to say the least. cheers

Pretty much none of the stock wheels will fit the Wilwood brakes anymore. The hub bore for the Wilwoods has to be 3.050" with their new redesigned hub, and that's larger than pretty much all of the stock wheels. The wheel studs used are also 1/2", so they won't usually work with stock wheels because the stock SBP studs were 7/16". And the rallye wheels don't clear the calipers.

So, there's really no advantage to using the Wilwoods to keep the SBP. You have to buy new wheels anyway, might as well go BBP. Heck, with a hub bore of 3.050" a lot of BBP aftermarket wheels won't fit either.