The areas that required grinding were only small spots that were of no consequence and of no value for anything regarding supports. They were really only taken down less than 1/32 inch and did not protrude through any sheet metal. There are a lot of lumps and bumps on the underside of the floor pan and tunnel that are nothing more than the result of the original fabrication process (weather original or aftermarket). I ground them down just a tiny bit past the surface, cleaned everything, then filled in the dimples (welded), and finally a final polish grinding to make it smooth and look like it was that way from the get-go. I didn't need to do all that, but then I am a ridicules stickler for detail and making everything clean. Even though I'll likely not ever see that area, but at least I'll know it looks good!!! Like most projects, this one started out to be a six-month project and ended up becoming a five (+) year project... and is still not completely done!!! My last project was a 33 Ford Tudor that also ended up being a six-year project. It was an amazing car and a real "trophy magnet", but finally had to go so I could move on with the Road Runner (wife rule - only one car at a time). This Road Runner will be my final car... a very fitting way to come down the home stretch with a car that looks almost exactly like the Road Runner I had back in 1969 (a daily driver and weekend racer). That Road Runner was an Ivy Green post car with a four-speed and 383, and ran mid 12's after some modifications. Although this Road Runner looks the same, it is significantly modified (well hidden) with a power plant putting out about 700 hp. I expect it to run mid 10's!! I may take it to a track one time just to get a time on it and if it goes into the 10's, I'll not be able to go for another trip down the strip without a roll bar... which is not going to happen.