[wtm442]

Dumb question. I'm not interested in peak HP and TQ if the problem is below 3500 RPM.

What does the dyno sheet show for the air/fuel mixture when you stomp on the gas pedal in 3rd gear at about 2K RPM? Does it go lean? Does it go rich? Maybe its just a few carb adjustments. Disconnect the secondaries and see what happens.

If you have an ankle problem, I'd suggest holding on to the automatic for now. If the carb is OK, the next thing to do is change the rear end gear and/or the first gear in the tranny. Then you could try the dual plane manifold. But before you do that, you could retard the cam to make more lower end HP, but it would decrease your top end HP.