Started working on the left fuel tank. This tank is about 1/2 inch narrower than the right. I filled it with fuel for a month to see if it would expand but it has stayed the same size. I cut some rubber weatherstrip and used it as shimms keep the fuel tank in place when installed. Installed tank and clecoed in place. So far it looks like this will work ok, but I may look for something else to shimm it with, maybe cork or something.