9" drums will stop it also, my real question is how much better if any are the 4 piston ones? I am planning on putting a really big small block in it with high gears for the open roads around here and I may need to stop in a hurry when a heard of antelope cross the road. If the difference is very tiny then I will probably go with the single piston one but if there is a significant difference I will deal with the hassles of hard to find stuff.