Disc brake conversion (70 Dart)
You forgot to mention that new wheels and tires may be required, as a lotta stock wheels won't clear most aftermarket calipers, particularly Wilwood. ! !
Another cheque, no problem !!
The guy just wanted to improve his brakes, not stop a 10 sec car. sheesh
Correct. The Wilwood hubs in the kits for A-bodies now require a center hole diameter of 3.050", which means stock wheels won't clear them. It actually means a lot of aftermarket wheels won't clear them either.
On top of that, the Wilwood brakes aren't better than the stock 73+ disks for actual braking force, so if you're hauling in a 10 second car the Wilwoods won't necessarily stop you any faster. And here's why-
The Wilwood kit for A-bodies with 15" wheels uses an 11" rotor, which is pretty much the same size as the factory rotors (10.95"), so no advantage there. And they actually have LESS brake piston area. The wilwood specs show the piston area as 4.80 square inches. Even the factory 73-75 A-body single piston calipers have a piston area of 5.3 square inches, and those are the calipers with the smaller 2.6" piston diameter. If you use the later '76 A-body calipers, or any of the B/E/F/M/J/R calipers with a 2.75" piston diameter they have a 5.94 square inch piston area. The Wilwood brakes
probably have less pad area as well. Wilwood lists the spec for pad area at 6.36. While I couldn't find an exact pad area for the 73+ disk brake pads, the length listed by raybestos is 5.610, and the height is 1.7" from the pads I have laying around. That puts the area at 9.5 square inches. It's a bit less than that because the pads aren't square, but, not by a lot. It's definitely not less than 7 square inches. Which means the 73+ Mopar brakes have more pad area as well.
Specs for the wilwood calipers
Wilwood High Performance Disc Brakes - Caliper Product Number: 120-13844-RD - Test
So, the physics says the Mopar calipers can generate more braking force. Now, the Wilwood brakes are quite a bit lighter than the stock stuff. And the multi-piston, fixed design will be more efficient at transmitting the braking force to the rotors than the single piston floating calipers Mopar used. But given the disadvantage the Wilwood brakes have in piston and pad area, I seriously doubt they put more force to the rotors than the 73+ Mopar brakes. Yeah, the Mopar brakes are heavy, and the single piston design is simple, but they've been proven over millions and millions of miles. Heck, that basic design came on cars from 1973 all the way up to 1989.
I'm not saying that the Wilwood brakes aren't nice, they are. But other than the weight they save, they aren't slam dunk better at stopping your car, and they're significantly more expensive.
