Just for conversations sake, conversions using the 68 and up camaro, and 68 amd up vette are really common and the guys with the passenger cars have been using those masters for years now. All drum conversion, you want a 1 inch bore master. For disc drum you want a master with a 1 1/8 bore.
Now, one small rub. The original single pot master had a pressure residual valve built in. One thing to keep in mind, new masters no longer come with pressure residual valves. Original gm dual masters had them and real professionally rebuilt masters had them but no more. The residual valve kept a little pressure on the back of the cups of the wheel cylinders and helped keep the shoes from completely completely retracting. You really should have them on an all drum system, and at least one for the rear brakes on a disc drum system. Wilwood sells their 10 pound valves that get plumbed in line, preferably close to the master.
https://www.moserengineering.com/260-1876-Wilwood-10lb-Residual-Pressure-Valve.itemIf you are having a real gm master rebuilt, have the rebuilder install the stock type duck billed residual valves.
let’s talk brake shoes. When these cars were new, brake shoes were made out of asbestos. Worked great as a friction material and the cars and trucks stopped just fine. good for braking, not so good for our health or the environment.
todays over the counter brake shoes use an organic material. What is in it, no one really knows.
in 2015 I redid a drum brake system on a 57 car I own. I installed new everything, including brand name shoes. Car would just not stop. Terrible really. I have owned and driven that very car for 47 years so I know exactly how the car should stop on drum brakes and those shoes were not doing the job.
A friend turned me on to Muscle Car Brakes and their ceramic matrix brake shoes. They are not inexpensive, about 120-130 for each of the front and back.
I bit the bullet and installed them and what a big difference. Stops just like it should. So in my mind, those are the only shoes you would want to use on all all drum system if you really want to do everything possible to improve the braking, and if MCB offers shoes. Call them if they don’t, they may be able to do a custom job, you never know.
http://www.musclecarbrakes.com/bib5170chevy.htmlIf your disc set up uses the chevelle D52 caliper, a common caliper to use, or some other type of common caliper, you might use some Hawk Street 5.0 pads. The more aggressive friction will also help get the truck stopped in better order then over the counter organic pads.
The master on the left is a camaro/GTO manual drum brake master. Next photo is the 68 vette style disc drum master. Hawk pads for chevelle caliper. And on the right, see the duck bill looking things with the springs, those are the pressure residual valves. Those come in a Raybestos rebuild kit. Original masters can be rebuilt with these valves installed. New masters do not have removable seats so no way to install them so you use the Wilwood inline versions.
One last thing, if using a gm style proportioning valve, remember to buy the little tool to lock the shuttlecock in the valve in place while you are bleeding the brakes. Otherwise it will trip and only half of your system will work. And they are a bit of a pain to reset.
https://techtalk.mpbrakes.com/proportioning-valve-bleeding-tool
