help with drum brakes

[Blackjeep99]

I have factory drum brakes I installed a new MC. The old one I took off was a reman delco unit the new one was exactly the same. I bled everything and now it pulls to the right. Everything worked fine before I replaced it. The old one work but was really rusty and leaked. The back seam. To lock up before the front do. I've herd bout residual valves but I don't see any in the lines or the old MC. I'm getin fed up with these drums and about to switch to discs and prop valve. I drive this truck a lot so I want it to stop safely. Any help is a big help. O its a 69 GMC swb