422 dyno fail

Jim Ward said

Well the intake and carb helped some but it is still lacking. Made 480ft lbs and 396 hp. I will put the motor in the car and then pay for a chassis dyno as in this session that I paid for I only have got 4 pulls. The cam was supposedly installed straight up.

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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.