Them days is about over. Government is involved now. Finding kits to swap automotive stuff was easy at one point, not as easy now. Swapping engines in powersports stuff? You get to pay someone to do it for you, or you can spend months/years doing it yourself.
Polaris seems to be the easiest to swap stuff into/around on and those aren't easy either....certainly doable, but a business of doing it would then have to get some kind of certification that their kit allows a newer/cleaner/quieter engine to be retrofitted where the old one came out. Secondly the numbers just don't work out by time you buy the CNC machinery to make the plates, clutch adapters, clutches, belts, electronics to make the new engine talk to the old ecu (or completely new electronics altogether...e.g., new harnesses and sensors and/or ecu(s)), etc
This stuff is NOTHING like cars and trucks. NOTHING, not even in the same galaxy as far as what you're speaking of
that engine has it's own unique mounting points, the transmission doesn't bolt directly to a "bellhousing" per say, the electronics that run it are specific to that engine and chassis only, sensors are somewhat proprietary to that engine, etc
as said I've been messing around with Polaris stuff and a lot of them are very similar but different enough that, things don't interchange-even within the same product line. You can't put a 850 engine in a sportsman 570 chassis. They're both sportsman ATV's right? SUre are...and they are TOTALLY different in almost every aspect. You can't just make an adapter plate for this stuff and bolt a chincanese 6 hp OHV lawn mower engine to a sidekick chassis and make it actually usable. Remember there's wiring fuel system primary & secondary clutch belt cooling intake and exhaust, etc to have to deal with....
Sorry, it's not as easy as it used to be, nor as easy as some people would want you to think
but if you have fab skills, electrical skills, efi skills, and ecu skills, a lot of time and probably money, feel free to do as you please
The amount of money you'd have invested in swapping stuff in, may very well exceed the cost of a replacement engine. THAT is why swap kits for this stuff aren't in existence. Money. There are so many differences that you'd need a LOT of swap parts, which means it'll cost a lot of money, which means it's simpler in the long run to put the factory engine back in. And stay legal, emissions-wise.
this subject came up many years ago when the Kawaski Mule 454 engines were failing. Guys would go pick up some snowmobile engine and "bolt them in". I did it as "the internet said you could" and I guarantee you that it was NOTHING like the "internet" says it was, it's a pain in the neck, lots of days of trying to align belts, clutches, finding a clutch to work with the new engine, removing the belt cover (it couldn't go back on so if you had any water splash, it slips), installing a new CDI, re-doing the air intake, exhaust, just a lot of work that "they" didn't talk about.
