Several people use zinc phosphate. http://www.eastwood.com/eastwood-zinc-phosphate-aerosol.html

Make sure you have the back down all the way by loosing bolts to fender and left up on the hood nose to force the back down then tighten bolts. Also make sure the middle fender hood bumpers are not to fat. I had to shave some of the rubber to make thinner.

If all that fails. Some slot the rear hinge holes some to make the back lower.