Some of you DIY's might find this a good way of passing large amounts of wire, battery cables or air lines through a body panel. It is a "Glad-hand seal" used in airlines on tractor trailers. The center hole is about 5/8" and can be made a little bigger while still providing good protection. They are available at any place that sells truck parts and are very cheap to buy. (Don't buy the urethane type).
You will need to make a 1-1/16" hole with a hole saw.
"there is neither science nor fact prevailing here" - vlamgat