Vastly stronger transmission. The internals mass also skims a lot of power right off the top, even relative to a TH350. For a street car it's pointless because you don't need the strength. For a drag car(or a truck) sure; bolt it in and have whatever changes made that are necessary in tune.
And it will work great on the street, but kiss your highway MPG goodbye.
Do not go gentle into that good night.
rage, rage against the dying of the light!