Brakes to soft after conversion

Any help. I did the scarebird front disc conversion on my 66 dart. rear it still the 9 in drums.
I changed out the master cyl with a newer 2 chambered version (1 for front, 1 for back).
I even install an adjustable valve that goes to the rear brakes, just in case.

I thought it was all fine, then I had to replace the rear diff gears, which meant pulling off the axles. Now reinstalled, had to adjust rear brakes a little.
But now it just doesnt stop fast enough. And I cant even get it to skid.
For experiement I turned the adjuster I installed that feeds the rear, and I turned it way up so the rear will barely stop just to see what happens. When I drove it it did seem to stop better which confuses me ho less rear pressure means better stopping upfront?
Any ideas here??
Fluid is in great shpae, properly bled, .
Is it possible that rear brakes are too tight??