I've got the self powered Mighty Mac chipper shredder. For an old late 80's Briggs motor that thing can do a lot of work.The MacKissic TPH-122 that I had for 16 years should work fine on it. Think it's only 300 #. Now TPH-123. There's also a chipper only model.
Gobs of hp on the X738. I ran the Mac on an 18.5 hp 4010, a 1025R and now the 2025R but have since gone to a much heavier WM WC46 chipper for horizontal hydraulic feed and don't need to shred leaves any more.
Did you get this at a Home Depot ?
This is the exact same setup that I use. Chipper to Gator, Gator to wherever I want the chips.