In 64 Ford used those behind the 427’s. Those were about 425hp, and 475 ft/lbs. Most stepped up to the 4 speed when they became available. But it’s somewhere in that ballpark. Probably the easiest way to break something is to use o/d in low where you’ve got full torque multiplication against the o/d unit. Or really sticky tires and side stepping the clutch. But they’re pretty stout units in general. I know there’s some variations in input shaft length and splines, but no idea of what that changes.
The Jalopy Journal
