1968 Buick Riviera, Should I take it?

Determine if there's ethanol-free gas in your area. If there's not and E10 gasoline is used in this vehicle it will result in fuel system problems.

The fuel system in this vehicle was never designed to be exposed to any concentration of ethanol gas. And because of this deterioration of rubber components and the corrosion metal components can occur.

Now if you don't mind taking the carburator apart each year so it can be rebuilt to replace the components damaged by the ethanol gas, then go for it.

Tester