4 wheel disk low pedal blues

1963 Plymouth valiant.

1974 Dodge Challenger front disks

1996 Ford 8.8 rear axle with factory disks.

1987 Dodge diplomat master cylinder. 1-1/32 bore.

Lines ran straight to hoses/calipers. No proportioning valve. Front to rear bias seems to be fine. No premature rear lock up or anything.

Here's the problem.

The brakes work really really well. But there's way to much pedal travel in my opinion.

Manual brakes. 2-3" of travel.

I'm thinking residual check valves are needed? I've plumbed them on other cars before when the master cylinder is mounted below the calipers, but didn't figure it would be a problem in this car. (With a standard master above calipers setup).

Any help is appreciated.

Thanks. Eric