hydroboost brakes with disc brake master cylinder

Hello everyone. After 4 years since teardown my 68 M715 is coming back together with a 350 horse 350 (on the dyno) adapted to the stock drivetrain.
The body is back original color with only one rust spot on the floorboard needing fixed. The bed floor was replaced with plate on a new frame due to 30 years as a brush fire truck with a leaky tank.

It is getting a hydroboost power steering/power brake system out of a 1978 K30 chevy. I have the booster mounted to the firewall with the modified pushrod (shortened, welded with additional reinforcing collar), and have confirmed full stroke. I had purchased a new master cylinder which I have installed on the booster.

In searching threads it seems some have just ran lines to the front and to the rear with no residual valves or brake proportioner (with stock axles for now). It seems with that larger front disc cylinder I will have some pretty big front brake bias. I have previously replaced the stock wheel cylinders with ones from Vintage PowerWagon, not sure if they were stockers or the Ford van cylinders. She stopped great before teardown with the stock system.

1) It seems that a manual proportioner valve in line would let me fix bias problems easily once I get it going. What are other's experiences?

2) Any need for residual valves with this type of master cylinder to prevent air being pulled back in the wheel cylinders, or do these wheel cylinders have the proper seals to prevent this?

Thanks in advance for sharing experiences. Next, I do the hydraulic clutch master cylinder!! (System is from a 1987 half ton chevy with hydraulic clutch).

Mike

This might be an apples and oranges kind of thing. But I will give it a try.

I have a Hydroboost on my M715. 1976 Corvette master cylinder and the lines run as you describe with the master cylinder split between the front and back. I have the Ford E350 van wheel cylinders.

My master cylinder has the same size pistons front and back. That is the apples and oranges part since yours seems to be different sized pistons front and back.

I have no residual valves or proportioning valves. My brakes are very, very strong. I was going through town the other day with the top off and a few police men on foot were walking with a tractor up to the main highway. We only have 5 lights in my town and I know the timing of them. I should have had a green for another 30 seconds. They over road the system just as I hit 3rd gear and about 20 mph and was just a few feet from the intersection.

Michelin XZL tires really howl when you lock them up. I got stopped and we traded humorous insults at each other while they walked besides the very old tractor across the road.

Hydroboost is great in my opinion.

I have a hydroboost/master off of a modern 2010 duramax.... what is the benefit from pulling the master cyl that came with the hydroboost?

I have 4 wheel disc brakes on mine so theres that difference but yes I plan on running a adjustable proporitional valve block with also a modern hydro-brake-switch.

Thanks for the input. I found a manually adjustable proportioning valve on Jegs but it is backordered for quite a while.

I think I will stay with this set up and put in the valve in case I need to do some adjusting.

I bought some of the nice flexible brake line at NAPA so now off to bending lines.

Thanks

Mike