IT tanks and plastics interchangeability

Hi I'm new here but have been checking this forum out and it looks about the best I've seen.
anyway, I have a 1981 Yamaha IT 465 that has no tank. It is also missing the back fender and needs the front fender and the entire front number plate and headlight asembly replaced. I am wondering if anyone would know:
First if the plastics (mainly the tank) and seat off of an 82 Yamaha IT 250 or an 78 IT 400 would fit and which you think would be better.
Or second if there is any place other than a salvage yard 2000 miles away or a store that wants tons of cash, that I could find what I'm looking for.
once I get a tank on it I can start riding it and fixing whatever else I'm sure is wrong with it. (haha) :ride: :)
I Really want the tank. All the other stuff I can rig up and live with for awhile.
I'm sure it will have other problems because it sat outside for 11 years but with some gas it fired right up (after teaching me to wear boots when kicking it over) so when those occur I will come back here and look around.
Thank you,
later little Mike

I already have a bunch of links from "My first Yamaha IT 465" in here. And some others.
Thank you for the reply Dirt Bike Dave, I am already looking at buying a running 250 or 400 (I've talking to the guy for a few days so thats why I asked about them first) and his 250 Looks just like mine but I cant tell if it has the funny "tube in the frame thing" for the rear shock or not, but other than that and the engine size it looks just like mine. So that sucks for me if it won't work. I've also seen some yz 465s and 490s like you suggest, but most of them a just a bit out of my budget range at the moment as a college student :)