I pulled an old Sears Suburban SS16 could been a 18HP originally, with an Onan twin out of the weeds, been sitting around for 15 or 20 years. I needed to do some dirt work on the drive. Wasn't worth spending a $1000 on to get a twin engine, I wanted an electric start too.Looked at reviews, and didn't want o spend extra $100 to get one from the china tool store locally. So chose the 420cc Bilt Hard, drilled the holes bolted it out and started on the third pull. I still hadn't hooked the electric start up yet. Starts easily.I've got about three hours onit so far, maybe a bit more, on the third tank of gas. Wouldn't know this classic from 1976 didn't have the 18HP engine on it, I've run at only about half throttle and it has more power than traction, and its dozer blade just pushes, hit a solid rock etc and the engine doesn't bog down, it just goes to spinning the tires and diggs.Time will tell how it holds up, so far, no complaints mechanically.The one gripe is there is nothing in the paperwork about wiring up a battery I seen, no specs on what the charging circuit or if it even has one, That is the reason for the four stars on install.....I would recommend the 420cc Bilt Hard to anyone looking to repower a classic garden tractor. It revived an old workhorse...Will it power a mowing deck? I can't say as I never intend to put a deck on this one, its just for gardening and dirt work....