I have a 1975 Tartan with an A4 and an aluminized steel gas tank. Tank looks to be 18 gal judging from its dimensions. One odd thing--it is canted foward, this is tipping foward about 15 degrees. This appears to be original. Looking to replace the tank because have been getting small chunks of rusted metal? in the Racor fuel fitler. Has anyone had a monel tank build, or reused an old one?