What Makes a Race Powerglide?

By Mike Bumbeck
10/8/04

eneral Motors introduced the aluminum Powerglide transmission in 1962. Since fully automatic shifting was a privilege reserved for much higher price models, the introduction was truly a milestone moment. No engineer could have possibly envisioned that the budget-minded Powerglide would eventually end up behind countless 1000-plus horsepower performance engines.

The race-prepped 2-speed Powerglide is the transmission of choice for drag racing and circle track drivers alike. Running a 'Glide is as common as the small block Chevy it's often connected to, but what keeps those internal parts from tearing themselves apart? There is no single modification that allows a Powerglide to stand up to the big horsepower. A series of internal changes add up to collective strength, and make a Powerglide ready for action.

We dissembled both a stock and a race-prepared Powerglide at B&M Racing & Performance Products to demonstrate what it takes to make a Powerglide stand up to serious punishment.

The input shaft is the key to strength and durability of the racing transmission. The 300M material is much stronger than stock, and the shaft is splined for use with a turbo-type converter.

On the left are the stock clutches. On the right are hi-power versions. The superior friction material handles the increased load for added capacity.

The all-steel clutch hub on the right is much thicker than the stocker. This allows for more clutches in the hub, which goes inside the direct drum. Lightening holes are also added. The stock hub is cast, and not nearly as strong.