If you have ever owned any of the tractor models listed in the title with a 46" or 50" deck then you know that the one fixed rear draft arm is notorious for cracking or breaking.  To fix this problem for good I got a heavy duty draft arm from a larger model that lifted a 60" deck and started to convert it into part number AM39336 which is the correct part used on the models in the title.  I have had dozens of these arms over the years and have never seen one damaged in any way after being used on the heavy 60" deck.

The arm was cut to length, had the end rounded and then bent on an industrial press to match the two bends in the 300 series arm.

This arm is both wider and deeper than the original.  It is 1.76" X .39" versus the original being 1.58" X .31".  So, it is 11% wider and 26% deeper than the original part.

To finish this arm two holes will have to be drilled into it, one for the 3/4" rear round lift rod and one smaller hole for the deck hanger.

Aside from some paint loss it is in excellent shape.  The last picture shows this arm next to the 300 series draft arm assembly and that assembly is NOT included, only the single arm shown in the first 3 pictures is.

I am parting out a 430, 420, 318 and 316 Onan so contact me if looking for something specific.