Salmon is correct. We see and hear all the time, about a PowerGlide, simply because it's a 2-speed. That's the ONLY similarity between ST-300 and PG. PG is a much better trans for performance applications, but in "light" cars. TH350 or 400 is far superior. Changing the ST-300 to a TH350 would dramatically change the "personality" of the car. It's a "bolt in" deal.