With a forum friend's advice I just installed a 6 1/2HP HF engine on my horse.All you need is a 3/4"IDx 1/8" thick shim to put between the pulley and crankshaft shoulder for pulley alignment. Drill the engine mount holes on the tiller out 1/16" for hole alignment and 4 8mmx1.25 pitch x 1 1/2" bolts for engine mounting. You have to fill the crankcase slightly over full to keep the low oil shutoff from killing it. My friend has used his this way for 1 1/2 yrs. I had to go w/ a slightly longer 5/16" bolt to hold the pulley on the crankshaft.
HTH,
Mike

I was at Harbor Freight about a week ago and they were closing out the Greyhound 6.5 hp for about $75.00

HF did away with Greyhound engine Predator engine took its place There should be coupon to help with new price Predator engine last I heard with coupon cost was 129.00