A powerglide? You mean Slush Box.
Thats what they called them in the 60's, because they were so sloppy that you couldnt get any performance out of them - At least a stock powerglide.
However, if you are thinking powerglide...you should spend the coin and get one that is built up. They work great for drag racing, but I wouldnt put one on a street vehicle, just not a good choice. Go 700R4 with a TC controller, if your not running an ECM.
At least you'll get decent driveablility out of it, and you can still take it to the strip for fun.