The biggest problem is that many people buy an off the shelf converter. Even if you buy a custom one, you really need a dyno sheet and the specs on the car to make it work properly. A convertor that actually flash stalls to 3500 behind a mild cammed car, is as you said, no good. You've most likely over shot the torque number, but maybe not, without a dyno sheet you are merely guessing and pissing the wind anyway.
Many people assume ported heads means more top end power or a higher RPM curve. This couldn't be farther from the truth. I just went from OOTB eddy rpms to max ported oversized valved eddy rpms, a ported single plane intake and a bigger roller cam. Peak power went up a whopping 100 (yes one hundred RPM). Power went up over 100 hp, tq went up 60ft/lbs. Another thing that surprised me is the carb, which was dialed for the engine prior to changes using an AFR didn't need to be changed at all jetting wise. Air bleeds needed some messing, but jetting didn't change.
