89 3.1 into a 98 GP...

I'm looking to swap engines out on a budget. I own a 89 Pontiac Bonneville w/ a 3.1. A guy I know has a 98 GP with a burnt engine. Can I drop the 89 3.1 into a 98 GP 3800 body/tranny? What mods am I looking at having to make to get it in there? Also, where can I get wiring harnesses for GP's? I will probably be rewiring the whole under hood as everything is charcoal.

Whether or not I get the car depends on your answers.

Thanks.