Auto Parts: Spark plugs, electrical repair service, world war 11

Question
Hello, Can you help, I have a 1960 Willys Hotchkiss Jeep, These were made under license in France after World War 11. It has a standard Willys Go Devil Petrol Engine. Electrics are 24 volt.Can you please advise which spark plugs are suitable. The workshop manual states Autolite 14mm. Kind Regards William.

Answer
    I'm going to assume that this is the 134 cu. in. engine that Willys used in just about everything back then.  It uses a 1/2" reach 14mm plug, Champion J8C.  A resistor plug, RJ8C could also be used, but I would use the non-resistor myself.  You could easily convert the vehicle to 12V by replacing the bulbs and having the starter and generator rewound by an electrical repair service.  The only reason for doing so would be if one wanted to use 12V accessories or be able to use an ordinary 12V battery.  If the Jeep is collectible, I would keep it the same, though.