Classic Industries OER front conversion question

A few years back I bought and installed OER MN5005B....front disc brake conversion kit with tubular uppers from classic industries. My question is what lowers will work with this kit?. Should I just rebuild my stock lowers or buy qa1 lowers. Also I’m going to stick with torsion bar set up. I’ve got a 318 I’m going to be putting in it with 904 trans and 8 3/4 out of a B body wagon that will need to be cut down to stock width. For the rear I’ll probably stick with drums. Also what proportioning valve and power brake setup should I go with. Im trying for a lower budget build. I don’t need anything super fancy. I just want to make sure I get compatible parts that will function well together.