Here is a video that shows how I put a 670 Predator in an older Walker mower. Turned out to be a fun project. I did the build in 2018, I have 30 hours on it with no reliability problems whatsoever.
Great job! Predators seem to do pretty well... i wouldn't put them on anything that when you need it, YOU NEED IT. But for tillers, log splitters, and kiddy go karts, they're good.