I have been working on and off in the conversion of the 72 from power to manual brakes.

For anyone else that is considering doing so, here are some points.

The brake bracket that mounts in the car is a pain to remove, but it is best to do so and weld some nuts into the bracket. These will be needed to mount the master cylinder later on. I used long set screws loctited in to use as studs.

The big hole from the power brake set up can be filled with a combination of fiberglass and JB weld. You can bolt in a piece a cardboard from the inside to use as a backer. I lined the cardboard with a plastic bag to keep the epoxy from sticking to it.

Make sure to change the brake rod position to the upper position.

You will need to make or modify a new brake light switch bracket, as you can no longer use the hole that it used to be mounted in. You can cut and then solder the 2 halves together in a shorter arrangement.

Purchase a new push rod and nut for the brake actuator. You may have to grind it down for adequate clearance in the master cylinder.

We had to use 2 different master cylinders to find one that gave a good pedal. The Delco one is the one we are using for now.

BRAKE PADS make a HUGE difference.
We started with RAYBESTOS SP8XP pads on all 4 corners. These brake pads have an FF friction rating and were able to lock up the brakes when the car had the power brakes. When we converted to manual, the pedal was hard and required what I consider excessive force. I was only able to lock the rear wheels with this set up. It was easy to tell the car did not have enough front brake. Even when the rears were locking the car was not slowing down hard enough,
In order to get more front brake, we tried a Carbotech Autocross pad. CT8-AX6. This pad is not marked with a friction rating. It was also noted that these pads do not have a anti squeal layer that street pads do. This should help in giving a firmer brake pedal. These pads required a slight grinding to make the pad pin fit.
but
Holy Moley do these things stop! In bedding in the brakes, the car would pull on one side or the other until the pads were bedded in.
Once they were bedded in, the fronts would lock but not the raybestos pads that were still on the rears. These pads are hella strong. The brake pedal is rock hard, and the effort to lock the brakes is just right. It takes a firm, but not ungodly press on the pedal to make them work, and the car stops with authority.

I'm looking forward to getting more time on them.

 

Glad you got it dialed in! Are you going to put the carbotech pads on the rear too?

 

Right now the balance of the bias between the front and rear is pretty good.
I need to get more seat time to see if it needs more back brake.

I think the autocross pads will be too strong unless I plumb in a proportioning valve.
Right now, the plan is to tune the system with the friction level of the brake pads.