Inliners International Forums General Discussion Vortec 4200 4200 parts - whats needed to help folks use this

I now have questions about the STOCK AUTOMATIC trans. that would come with an '06 or later engine. Which one did they use (4l60E, 65, etc.) and would there be any problem putting one in my '54 Chev, such as size - as compared with using an earlier automatic overdrive.
I'm thinking in terms of purchasing an engine/trans as a unit from the same vehicle.