they came with 8 and 9.5 hp engines the shifter cables are hard to find but you can get them on ebay for 39.00 paste this into ebay search. MTD 746-0935A, 946-0935A CABLE TRANS. SHIFT.OEM i just got 2 of them for 69.00 they are a bicth to install unless you do some dismantling. i placed my eyes on the end of my fingers and managed to get the top cable on the trans shifting lever under the frame. not bad to hook up at the top. but watch it when you test it. they are easy to get backwards. so start it run slow shift into reverse and push the go peddle and see if you get it correct if not just switch them
the yard man model is 13a=328-402 and for the guy that said they are slow must have 6 ft legs because i can mow my yard in 1/4 the time it takes to push the walk behind that is self powered.
if you need any more numbers just ask. i like mine but i hate the way it cuts. leaves the grass down from the front tires and then that grass grows and it looks like the deck did not do a thing. i'm trying to figure out how to get a high lift blade for it to make the cut even. the 3 in 1 blade just won't do it. i don't bag just side discharge and mulch. thanks good luck