FOR ANYONE INTERESTED IN THIS PROBLEM, I FOUND THE SOLUTION. IN THE OLDER (1950’S) MERCURY ENGINES, THEY USED A KEY MADE BY A FIRM NAMED CLUM. CLUM MADE KEYS FOR EARLY (1920’S) CARS UP THROUGH THE 40’S AND BEYOND. ALTHOUGH SIMILAR TO THE KEYS USED IN THE 70’S AND BEYOND, THEY ARE NOT THE SAME AND NOT INTERCHANGEABLE. AS FAR AS I CAN TELL, CLUM NO LONGER EXISTS SO YOU CAN’T GO TO THEM, HOWEVER TWO MANUFACTURERS ALSO MAKE THE BLANK KEYS AND THEY ARE AVAILABLE ON EBAY. THEY ARE ILCO AND TAYLOR. IF YOU LOOK UNDER ILCO, YOU NEED KEY BLANK 1040 AND IF YOU LOOK UNDER TAYLOR, YOU NEED KEY NUMBER 40. BE CAREFUL WITH ILCO AS THEY OFFER MANY VARIATIONS OF THE 1040 KEY, NOTABLY 1040B 1040E, 1040U ETC. YOU DON’T WANT ANY OF THOSE. YOU WANT THE 1040 WITH NO LETTER DESINGATION AFTER THE NUMBER. SIMILARLY, INTHE TAYLOR KEY, YOU WANT KEY NUMBER 40, NOT 40A, 40B ETC. I ORDERED THE ILCO 1040, HAD IT GROUND BY THE LOCAL LOCKSMITH FOR 2.00 AND NOW HAVE MY SPARE KEY. THE KEY BLANKS ARE NOT CHEAP, THEY WILL RUN YOU 8.00-15.00, BUT YOU CAN FIND THEM. THE LOCKSMITH DID NOT HAVE THE CORRECT KEY BLANK, BUT WAS ABLE TO POINT ME IN THE RIGHT DIRECTION SO I COULD FIND THEM.
HOPE THIS HELPS SOMEONE.
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