Chevy Al 1 1/16" bore

[Dave1695]

I used to work for an aftermarket brake manufacturer as their tech adviser. With MC on firewall, you do not need residual pressure valves, they are only used when the MC is mounted lower than caliper/ wheel cylinders ( as on a Hot Rod) to avoid fluid drain back to MC. A 1 1/8 inch bore is for power assist brakes, use an aluminum Corvette style MC with one inch bore, and an adjustable proportioning valve in the line to rear drums. It will allow you to regulate pressure to the drums and avoid rear brake lock up. Just my two cents.

[Eman]

https://www.dragstuff.com/techarticl...sterCylPN.html
Here's a list of sizes and part #'s for Mopar style aluminum MC's.
No matter what MC you use be sure you have a way to retain the pushrod so it cannot drop out of the rear of the MC. A good top pedal stop and a guide for the rod is important. Last year a racer at a local track in a car that was bullt and raced for years had an incident. His foot caught under the brake pedal and he pulled up hard enough to get the rod to drop out. He went off roading and was lucky.

[Todd Hoven]

I know this is a popular opinion among racers and street guys. I found different results. When I bought my Firebird I replaced and replumbed the whole car. I called a few aftermarket brake manufacturers about the proper way to go about it. Mark Williams and Strange’s opinion was adjustable valve in the front lines and the residual valve to the rear line. Some of the others had the opposite opinion.

You have a greater chance of locking up the fronts because of less tire footprint to the ground. The reason of the residual valve in the back with drums , is because you need quite a bit of pedal travel and fluid flow to get the rear brakes to activate, compared to the fronts with aftermarket calipers. What happens is the front calipers seat the pads hard and the pedal stops traveling. When this happens the rear shoes lack holding pressure and you have an extreme bias to the front. This makes it hard to hold on the starting line.
I can foot brake my car to 4000+ on the starting line and when I hit the brakes hard on the other end it almost never locks them and if it did it was the front doing it. The pedal is high and firm and the brakes seem to wear evenly. Just reporting my results and opinion.
4 wheel disc systems doesn’t need any of it. Just the drum setup. Do what you feel is right.

Originally Posted by Dave1695

I used to work for an aftermarket brake manufacturer as their tech adviser. With MC on firewall, you do not need residual pressure valves, they are only used when the MC is mounted lower than caliper/ wheel cylinders ( as on a Hot Rod) to avoid fluid drain back to MC. A 1 1/8 inch bore is for power assist brakes, use an aluminum Corvette style MC with one inch bore, and an adjustable proportioning valve in the line to rear drums. It will allow you to regulate pressure to the drums and avoid rear brake lock up. Just my two cents.

[Todd Hoven]

The problem with the stock Mopar MC’s is you have to use different size line bushings to hook your lines up. With the Strange it takes the standard and comes with a pushrod

Originally Posted by Eman

https://www.dragstuff.com/techarticl...sterCylPN.html
Here's a list of sizes and part #'s for Mopar style aluminum MC's.
No matter what MC you use be sure you have a way to retain the pushrod so it cannot drop out of the rear of the MC. A good top pedal stop and a guide for the rod is important. Last year a racer at a local track in a car that was bullt and raced for years had an incident. His foot caught under the brake pedal and he pulled up hard enough to get the rod to drop out. He went off roading and was lucky.

[Eman]

If you can flare tubing you can buy the line nuts and not use any adapters if the adapters bothered you. I used a new replacement MC for an 85 Chrysler and made the rod. I removed my pedal support and welded in a plate with a hole to guide the rod and it cannot drop as the MC has a shallow hole in the piston.

I have disc/drum and no residual valve in the rear and have plumbed others and never used a residual valve if the MC is on the firewall. I have an adjustable proportioning valve in the frt. line but it's wide open and don't have any problems holding the car at 4k. If you want more rear pressure applied to your brake shoes simply increase the diameter of your rear wheel cylinders.

[Todd Hoven]

Sounds like your deal works pretty good. Lots of different ways to get the same place. Race on