My theory is it is bad enough fixing what belonged in it originally,whether it be a car,truck,snowblower,tractor,etc...if you have all the parts ,why not put them to use?...it'd be the easiest fix..
I know many folks are ditching their old Tecumseh's because of parts availability issues and costs since they went under,and dont blame them..but I liked my old "Sno-King" Tecumsehs,they held up pretty good and seem to run better and start up in cold weather easier than Briggs engines..
Its not too hard to adapt one of the honda clones to many snowblowers--but if yours has the "double shaft" engine,you'll lose reverse --and you may need to drill new holes,buy a different pulley,etc..