Block sanding is what makes cars straight. The repetitive process of sanding a panel over and over again removes high and low spots in filler or surfacing primer, helping you achieve an arrow-straight panel. The downside is that it really isn't any fun to do. Here, Mark Poole blocks the Chevelle with a Durablock sanding block from Eastwood and some 3M paper to flatten the panels for a mirror finish. Discuss this project at today!