Most every gasoline powered vehicle built before 1970 was designed to operate on leaded fuel, and Kaisers are no exception. The lead in the fuel acted as a cushion to help valves and their seats last longer. When lead was phased out, manufacturers started using hardened valves and seats to prevent issues with seats receding.
I've read where a few boat docks and some gas stations (there's one near me) still sell ethanol free fuel. But that doesn't solve the issue of the missing lead.
Your best bet is to ensure you have a fuel system that's been upgraded to handle today's low quality gasolines. Fuel pumps and carburetors can be rebuilt with material that will stand up to the corrosive effects of ethanol. And, there are additives available to help with the no-lead issue as well.
I would first make sure your car has the latest fuel system upgrades. If you plan to drive your car alot, then I'd also look for a good lead substitute. If you're only driving the car occasionally, then I wouldn't worry about an additive. My 53K has had 10,000 miles of unleaded fuel thru it without anything more than an occasional bottle of Marvel Mystery Oil in a tank full of gas.
