I'm cleaning up the underside of my 67 drag car. I will be painting it with POR 15. There have been some patch panels installed in the floor and I'm thinking of using the POR PATCH product to fill the overlap seams. They weren't welded on the underside. Also I have rust around the rear wheel well lip where the tub and fender meet. It is pretty bad but following grinding etc. the rust doesn't appear to have attacked the actual fender just the inner fender and the area where they are welded together.It is still pretty sound so I don't want to cut it out etc.and I'm trying not to get into the body of the car as it looks pretty good. Remember I'm not trying to restore this car just get it clean and presentable. Anyway I thought I'd clean and treat this area and then use the POR PATCH product to fill and smooth the area so it doesn't look so rough. What do you think? The other option is to treat it with a rust converter and then lay in alittle fiberglass to smooth out the area.Suggestions will be appreciated.

For the overlap seams, I recommend a brushable seam sealer like the they use at the factory.

For the rear wheel lip you might try some Por Putty. If it's a small area, you can fill it with the putty and shape it and paint it. Keep in mind that the only real way to repair the rust is with a patch panel. The Por Putty will probably work for what you're wanting to do.