I had the same problem, it was the ignition switch, I see you checked it, but Id just replace it if i were you, only costs 10 bucks, that also fixed a bunch of little problems I was having too.
Im sure the posi was rebuilt when they did the R & P swap, but they might have forgot to shim the clutch packs or used to small of a shim.
to test, just hammer it, if it gets sidways the posi is working, if it spins but stays in a straight line posi is bad/improperly installed
I think your good either way, I just installed new uppers (J&Ms tubular) w/ poly bushings in the uppers and I also installed poly's in the axel housing (your gonna have fun removing those, haha) in place of stock uppers with really old bushings (all 4). Its way better, had slight wheelhop before...
I actually just sold a B on ebay for like 150shipped, @ 2 months back, I was really surprised, only expected it to go for like 50 bucks
Ive ran the B, X, Z and the holley systemax cam. I really like the Z, I do wanna try a TFS stage 2 though.
I do mine exactly like he said, but with red rtv, which i let setup for @ 15min before dropping on the intake
Im with you on the torque wrench thing, I know some people who are torque wrench nazi's, haha
for that 15 seconds nothing else maters, not my GF's huge sunglass's, not the monthy payment on my bling bling, not my tires with full tread left on the outsides but showing cords on the insides,ect.,ect.
Im guessin its leaking through the valves, not the rings, but you can squirt a tablespoon(@) of oil in the sparkplug hole, then test it again, if psi goes up then it is a ring problem
ps- its good to prime the oil pump anytime it sits for a while (just before starting it)
haha, very stealthy set-up indeed
IDK why 10lbs are the most common, things only give a few good shots, I use to have a 20 pounder, thing worked great but i sold it like a dumbass