Not sure if the front end will swap -- seems like anything can swap with enough work. But if it does, you're going to have a very modern looking 17 inch wheel in the front with a 120 tire that is wider than anything the rear spoked 18 inch wheel can accommodate. I suspect that any suspension improvement from the forks would be completely overshadowed by the clown steering/handling that would come from such a weird combo of wheels and tires.
I hadn't heard about the carbs being compatible, but if they really are, I'd love to hear about it.