Ooops, it looks like earlier 216 and 235 engines used different plugs?

1937 - 11mm
1938 - 14mm
1939 - 14mm
1940 - 14mm
1941 - 10mm
1942-46 10mm
1947 10mm

I'll look up and add/edit through 1947.

Last edited by tclederman; 12/28/2016 4:43 PM.