I've been building this 87' from ground up, started with a junkyard bike, already had to helicoil a couple bolts in motor and drill out a broken bolt, none of which was my fault it came that way, did Versi head plug an ALOT of various other things/ REPAIRS. I've been building it for the last year and even though I've only road this bike a few times in the last couple weeks I've fallen in love with it and will not give up. That said, I went for a ride last weekend notice a little oil seeping out a couple bolts intop of head so went to re torque them down and they were both loose, one broke off, it's a long one and other stripped out the hole also a long one, every time I ride it seems like motor bolt even torqued to spec keep breaking. There's a 96' for sale in my area with 1,300 origal miles on it so I was thinking of doing a motor swap, how easy is that or is it even possible, I know there some differences in electrical but just wanting to explore my options. Any info will be grateful appreciated.

I prefer the newer hardware, so if you swap engines I'd also swap the wiring harness and all connected to it.
use the TCI (ignition box) that came with each engine, otherwise you need to swap rotors as the timing is different between the bikes.

I have a 95 motor that has the top end off and both cases open, which the engine failed due to a snapped cam chain tensioner.  If there are random parts you need let me know and I can see what's there.