A few years ago I took apart an older 235 in which somebody had drilled small holes and pressed little nails in tightly so that the rope seal would not be able to turn nor shift...top and bottom. The nails had been ground (like a knife edge) so they had little raised metal lines which stuck up about 1mm from the surface of the channel. I figured they thought that would be more effective than a single sharp point. I think I still have the image of it. I'll look for it sometime.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end