Should I sell

Anybody who thinks gas prices will affect classic car values is kidding themselves. If you use your classic car as a daily driver and its gets millage in the single digits with the war in the Ukraine and sanctions with certainly affect gas prices, you may consider a more economical vehicle
The prices on used cars are at a all time high, why would classic's fall in value? How many people use a classic car with a big V8 that gets terrible gas milage for everyday commuting?