Need some brake help/advice

[Broncojunkie]

I've been fighting with a brake problem on my pace car for a while. Since I restored the car, I went ahead and pretty much replaced everything except for the brake lines on the front half of the car and the booster. Everything else is new. After bleeding them multiple times, I still have little pressure and hardly any brakes. No air appears to be coming out when I bleed them, nothing is leaking, and wheel cylinders and calipers are brand new, along with master cylinder and all soft hoses.

At this point, I'm suspecting that the new master cylinder is bad. Before I go replacing it, what do you guys think?

Also, I'm planning on doing a 5-lug swap this summer. I already have an 87-93 booster and 94-95 spindles, control arms, rotors, calipers, etc. Should I go ahead and replace the booster with the larger 87-93 piece and use a newer master cylinder? If so, which MC works best with the larger front brakes? I'll be sticking with 87-93 drums for now (I'll be swapping the 7.5 rear for a fresh 8.8 very soon).