According to Willys America Guide/parts book the L head 6-226 used 1954 -1965.
wagons to '58 before eng.# SW-6L 14188/ TW-6L90919, '59-65 after those #s.
never mind - I just came back to picture to realize it's an L head 134 - I'd better have more coffee cause that'll take a lot more digging in my pile o' books - they used them for a couple of decades I think... including '50.