factory flaw in a muffler?

mikedevore said
You mentioned the t-convertor being a turd, is it possible that this is the problem & not the muffler? Whats wrong with the convertor?

I have gone over the converter issues over in "transmissions". My engine builder reviewed in detail the motor specs with Dynamic to see what would work within my budget. They feel a 9 1/2" race converter is the cure-all, but told him the 11" street would work fine for me. Dynamic claims 2600-3200 stall with the 11" street unit. Not even close! Basically heres the converter problem- the converter locks up right off idle.. ZERO flash RPM. My brand new stroked smallblock which made 430 HP and almost 450 Tq 4 weeks ago on the dyno feels like a stock smog 340. I have a new custom converter coming in about 2-3 weeks.
I know this will fix the off idle power, low end and make for cool holeshots but my brother feels "something" is really holding the motor back at higher RPM. The car should be absolutely terrifying with obscene traction problems. You know the tranny has been freshly rebuilt as well, have heard that too much throttle pressure can kill your performance if he (tranny builder) F'kd up something with the pump.
I know an internal flaw with one of the mufflers is a reach..but that could mess things up.