gas tank c4 89
 

I am about to install a new fuel sending unit. The opening to the gas tank had some rust with some pitting and flaking. I sanded most rust off and put naval jelly on the rest and painted the opening.The problem is that I don't think the gasket will seal properly. I think I need to use gasket sealant because of uneven contact area. Would anyone please recommend a proper sealant?