Bolens Husky also had the Wisconsin 12D, should be a direct drop in replacement.
http://www.google.co....58187178,d.cGU
The one you posted pictures of is not a TRA12D. Looks like it may be a S12D which is an entirely different engine and will not fit without some serious mods being made.
As for the video..... If you want things original don't do what that guy does to tractors!