I'm sure the OP knows the Uly will only take an XB motor, but on the off chance he doesnt, or someone else reads this later may learn
something before they go that route. I'm not saying its impossible, and every now and again some knucklehead on FB says "i have a welder, i can make it fit bruh"
Also, $2k is a steal for a Uly. Even if the motor is junk, he could possibly rob the heads off it and resell them (as long as their rebuildable) they're worth $500-600 on their own, which takes the Uly price down to $14-1500.
In addition, who knows how complete the OP's motor is. He may need parts like a primary cover, motor mounts, starter, etc. etc. At least if he gets this complete bike and wants to use his motor, he should have all the parts needed to complete the install.
If he winds up with extra parts, he can sell those off to offset the purchase price of the Uly. Seems like a win-win to me.
Of course, thats if the bike is even still available, and if its reasonably close to him.
And if he doesnt want to take my suggestion(s), no harm - no foul, just throwing ideas out there.