what is this tank from?

I just got my old KZ1000J2 back after a seven year absence. The PO put a different tank on (LTD I think) and it bothers me. I went to a salvage yard and bought what was supposed to be a 1982 J model tank. It seems large, it is red underneath and I think it is from a GPZ. Problem is, the tunnel is too narrow for the '82 J frame. I LOVE the way it looks when I put it up and use a little imagination. Any ideas what this is actually from?

Yep...that is a KZ750R1 (aka 1982 GPz750) fuel tank...and the tunnel is narrower than the J tank tunnels. You like the look of the GPz tanks and if you find one, only buy it if it is a 1982 GPz1100 tank...that is a direct drop-on for your bike. Don;t buy the 1981 GPz1100 tank as the petcock location interferes with your carb placement (the 1982 tank does not interfere with your carbs).