OK, one thing jumps out at me immediately: it's nosing over. Torque peak is 4K, it's down 30ft-lbs at 4500 and 60ft-lbs at the 5000RPM power peak. It loses 100lb-ft in 1400RPM.
Clearly, something is choking this engine. My first question is one I haven't seen, though I admit I haven't read all 6 pages of posts: how big were the headers? I wonder if the shop's "SB Mopar" dyno pipes were small-primary. I think this beast needs decent-sized (1 3/4", maybe 1 7/8") header primaries.