RE: Serpent rear end wont sit tight
Nope. 4wd 2 drive belts. The rear gearing has a shaft coming out of the side. There is a pulley on that shaft that accepts the first, short, drive belt and it connects to a shaft close to the middle of the car which has another pulley on it which accepts the second belt which then connects to the front wheels shaft pulley. I hope that was understandable.
I could make a rough sketch for you on paint if that helps.