Brake drag after residual valve install?

[7T2]

On my 57 GMC, I installed a new modern master cylinder kit to replace the old, single reservoir setup. The truck has discs in front and drums in rear. The kit came with a combination valve for a disc/drum setup, so it should have the 10lb residual valve going to the rear.

After it was installed I discovered I also needed a 2lb residual valve for the front discs, because the MC assembly is mounted below the cab/calipers. Today I got around to installing it.

What I notice now is that I have a very hard time turning the rotors by hand now. That doesn't seem right, but is that normal for a system with a residual valve installed? I don't think it did it before, but to be honest I can't remember.

Should there be any kind of drag in a system like this? I know it's hard to describe the resistance over the internet, but, with the engine off, it is very hard to turn just the rotors by hand. I can do it, but it's tough. If I mount a wheel and tire it is easier to turn, but it still doesn't turn freely (i.e. I can't just grab the wheel and give it a spin, but I can turn it to where I want it to be. If I stop, it stops.)

Is this normal, or do I need to do some more troubleshooting?