Brakes sticking a lil do I have right prop. valve and adj. on brake rod?

[oldblue1968chevy]

If im at a drive thru or someplace on a slight hill I can be in N and the truck doesnt roll w/o putting in gear and giving some gas. Its a 3 spd. manual. It just goes' errrghhhh' (brakes just barely holding it back).

New Calipers rotors (now have slight groove). Pads Soft lines f/r ALMOST new hardlines (except here and there). New MC booster. Prop. valve is idk how old.

Here is a pic of rod/firewall. It doesnt seem to adj. any more than this.

Someone on here told me to check my caliper bolt bushings or something.

Also, My front wheels are covered in brake dust after a few days. I mean dirty. This doesnt seem normal. Thankyou.