Comment
Hi Kalle..What about 39-45?
...1936/7 was 5/16", 1938 was 3/8", 1939 onwards (all years) was 7/16".
Early engines had cylinder head and valve layouts that were quite different to the later types and 38 was an 'in between' type. From 39 onwards no major changes were made. Timing was altered to suit the different types..Ian
email (option): ian@wright52.plus.com