Re: fuel gauge
Your gauge is going bad. I've seen this in a few of the older Chevy trucks that a relative had. The sending unit is ok, but the gauge end should have a damper in it to keep it from moving too fast. If you can take it a apart, a little bearing grease on the pivot will help, otherwise replace the gauge or live with it.
1955 Willys CJ5 Buick 225 V6 160HP 270ft-lbs, T90 trans, Warn OD, PTO winch, Spicer 18 T Case, RS9000's, Dana 25F/ 44R,
5.38:1 gears, 11" brakes, Bestop Supertop, Hurculiner