What's your timetable? Are you wanting to minimize your downtime, or is having your ride out of commission for month or more during the good weather OK? If you're in a hurry and wanting reliability buying a crate engine from a reliable source is probably your best bet, but you're going to drop around $4K to get a "built" engine. Like MP&C says, you might also be able to find someone wanting to upgrade, but then do you truly know what you're getting? Lots of kids out there who think they can simply throw a new crank in their old block to make a stroker and then pass it off on someone as "rebuilt". Also lots of "crate engines" on the market with rattle can rebuilds (pull, power wash, paint & sell). The old adage, "Let the Buyer Beware" is especially true for engines.