engine swap question

[wesman]

Hello to all,

This is my first thread, so please bear with me. What problems would I incur by swapping the engine from a 1986 xt600, into a 1990 xt600?
The only thing I have came up with is that the 1986 has the separate oil tank behind the left hand side panel and the 1990 keeps it's oil in the frame.
On the surface, that doesn't seem too scary to tackle. My other worries
would be in the engine/swingarm mount and other unknown obstacles. I have
a chance at purchasing an entire 1990 xt600 with a train wreck for an engine. I've been trying to weigh the pros and cons of this idea in my head.
I need advice in a big way! Would this be worth the trouble or should I just
keep riding the '86 as she was meant to be? There's not much wrong with
her, except the suspension could probably use a refresher. Any benefits?
I've never ridden a '90 xt, so I can't compare the two. Sorry for the length
of my thread! I will go now!