120-7381 Wilwoods on 73+ spindles

Looking to upgrade to a four piston caliper on the front of the car. I already have 11.75" plated/slotted rotors upfront that I just put on last year with new Timken bearings. If possible I'd like to keep the rotors. I see that Dr. Diff offers the necessary parts to bolt on Wilwood 120-6815 calipers on. These don't have dust seals though and are ear mount.

I would like to use these:



120-7381. Almost the exact same caliper, but with seals and radial mounting.

I know Andy offered a bracket to mount these to earlier spindles. Anyone know if there is a bracket to attach these to 73+ spindles?

Thanks...

I used to make a kit that mounted those on the big spindle knuckle. Nobody bought them so I scrapped the parts and deleted the part number.

I will be in the market too for an upgrade on my (front) brake system on my '73 Dart.
Currently running stock C-body calipers on '73 C-body rotors (1.25" x 11.75").
Year-round daily usage and winter roadsalt aged the calipers
I like to get rid of some unsprung weight and start by using aluminium calipers w/dust-seals, and maybe lighter rotors too in the future if the price is friendly.

The problem I ran into while checking things out at the time, was that the 4-piston Wilwood caliper has a smaller combined piston-diameter than the current 2.75" ø factory C-body caliper, which would be a 'step back' and also offset the brake-bias.
Also most calipers, as is the above one, don't fit the 1.25" thick rotors.

I make a brake kit which mates first generation Viper calipers to 11.75" x 1.25" C-body rotors and B-body drum knuckles.

I even have 35 pairs of NOS Viper front calipers in stock.

https://www.doctordiff.com/viper-caliper-mounting-brackets-for-mopar-drum-knuckles.html

The 11.75" rotors I have on the car now are 1" thick. Was hoping for an easy solution to a 4 piston caliper using the rotors I have on the car now. If I have to replace the rotors it's not the end of the world.

Cass, I'll give you a call after the new year. Thanks.

Any updates on this?

I ordered the second caliper and SS flex lines from Summit. Trying to figure out a conversion to manual brakes at the same time. This was something I wanted to do last year, but never got around to it. The F/J/M cars have a different stud spacing on the booster than the older stuff. The horizontal spacing looks to be the same and the vertical I should be able to just drill a couple hols in the firewall. The way that the brake pedal bracket is made it should work. This should allow me to run a Baer master cylinder with one of your adapters.

Slow moving though with Winter though.

Finally got some garage time in and I took it to both mock up the calipers and measure the piston diameter on the rear calipers. It basically fell right together - looks great.. I just need to figure out what master cylinder I'm going to need (that'll be a separate thread) after I get the pedal ratio.

what caliper mount did you use?

They're from Andy at AR Engineering, but that kit was discontinued. I got lucky and he had one last set laying around.

Andy, just wanted to give an update and say thanks again. Got the calipers on and took the car for a long trip with a couple passes on Woodward yesterday. Performed great.

Glad to help. The Wilwood calipers are light weight and fairly inexpensive but the piston size is fairly small you you have to pay attention to your braking force. If you find that you need more stopping force you can always switch to a more aggressive pad. Wilwood makes about 10 different pad compounds for those calipers.