Do I need a new mechanic?

I got more seat of the pants torque with just changing to the
RPM air gap. I really dont think you need the spacer.
Mine is a 340 with a MP cam 484/242. headers and X pipe.
Try it with out the spacer first.
I just fit it under the hood in the Duster with a 4 in filter.
You shouldn't loose any power and torque.