The 50" deck Zero turn that I'm rebuilding from fire damage had a 691 cc (42 ci) tecumseh vtwin on it. Since shroud burned I don't know exact model or stickered HP. I'm hoping that I can restore it but I'm currently waiting on back ordered gaskets. I've been looking at options. I have a 17.5 briggs 31 series that may run ok but that seems a bit small. One option is to swap it with the briggs Vtwin on my mtd since I plan to use mtd for snowblower only. Funny though I think that mower unit is labelled 18.5 HP although engine is same as our church unit labelled 20 HP. But they say there is no replacement for displacement so how about a 42 ci opposed twin? But the HP on them varies starting at 14 hp and maybe up to 20. So I was looking at some JD mowers at Lowes. Both had briggs vtwins of 743 cc (IIRC) but one was 22 HP and the the other 25 HP. Now I see this HF vtwin of just 703 cc but rated 25 HP.
https://www.harborfreight.com/engines-g ... 62879.html
Dog's breakfast as my Dad would say.