I doubt they are the same. The standard 3 speed trans is about 15" long.(Measured from the bellhousing mount to the end of the tailshaft). The powerglide is probably about 5" longer.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine