if you have no rust soda blasting if the best finish as it isnt as abbrasive as sand blasting my gt 80 motor looks like that at the moment i found a rock in the tank and it was from my old house as i could tell because we had that type of rock on the drive way which was huge i must have put the rock in when i was 11 or 12 unless my little brother did it we might have thought it would add some more octane to the fuel.