I have to disagree, the PG will ET better. The 5500 converter will launch the car quicker and the PG will not launch as violent as a TH400. The rotating HP required to turn the TH400 is 15 to 20 horses more. And 3500 lbs is NOT too much weight. Who ever told you that lied to you. I had a 3400 lb Chevelle with a reasonably mild 400 SBC and ran at least a tenth quicker than a TH350. A three speed (ultra light, ultra$) will be marginally faster than a PG in a Comp style car/engine tuned to a narrow RPM range. You will be much happier with the PG.