Originally Posted by PBA

The surface is not heat treated. I agree, take off as little as possible. You should end up with a mirror finish if possible (600 - 1,000 - 1,500 grit sandpaper), for the most drum surface to band contact. Use the Borg Warner Hi-Energy band for the best all around results, no Kevlar ever. The BW Hi-E band with the right servo can easily hold 750 to 800 horsepower, when using a 10" or smaller diameter torque converter.