I replaced my PG with a TH350 that I bought from Summit. At the time it was $600 and now it is closer to $700 and is made by TCI. I also got a matching torque converter and flexplate. The swap was simple. Just make sure you get the 6'' tailshaft housing. Fit with no mods to the crossmember or driveshaft. The only thing I had to swap out was the trans selector which you can get for $5 at Rick's First Gen. The addition of a third gear is very fun.
The converter stall speed is determined by the cam. If you are running stock, go with TCI's "saturday night special," it gives around 2000rpm stall. If you are running more cam, then ask the summit tech guys and they will let you know what will be a good match.
[This message has been edited by boodlefoof (edited 04-30-2001).]