Good news, all the diagrams of the 2 hanger assembly's I have found on the interwebs are identical. I don't have the parts mower in front of me but I printed the diagram for the 46 deck and tore my deck off and every bracket and pin look to be in the exact same locations. Next weekend, I will go get the parts tractor and deck to test my theory.
2 things come to mind that I may have issues with.
1 I only have the 16 horse techumseh engine where as the parts tractor has the 18.5 Briggs. The 16 horse on my tractor doesn't have a problem slinging grass with the 2 bladed 42 but how will it handle the added capacity of 3 blades? My theory it that I'm only cutting 4 additional inches of grass, with 1 extra blade. So I'm thinking the additional load (4 inches) will be distributed better with 3 blades. Which may put less of a load on the engine. Or, will the additional 4 inches be detrimental regardless of number of blades?
2. And this may be a question for the engine forum or a different thread, but it seems that my engine does not have the rpms it should. It doesn't seem to rev out and have the same sound as other mowers. I've messed with the throttle linkage and it is getting full throttle on the govener which is vacuum operated. I can manually pull on the throttle linkage and get more revs out of it
That may sound stupid but I build race cars and high horsepower small and big block Chevys often so I'm used to listening to an engine and judging things like that based on sound.