Thanks for the advice. I certainly don't want to spend money and time and end up with results that are less than what I have. As I said earlier, I'm not trying to get more performance out of the truck, just faced with having to do something now that the tranny has died. The thought of lowering the rpm's to achieve better gas mileage was very appealling. This fall I moved my son to Grand Prairie from Calgary and the best I could do was 17.3 mpg with a tailwind for a few hours. At 70 mph (110 kph) it is revving 2700.
If I just get the th350 rebuilt, it was mentioned to get a 2400 stall converter. This would only give startup a boost and have no effect on anything else, right?