Will a '49 (late) - '50 Olds 303 distributor work in a '51 303. They have different part #s (1110817 vs 1110824), and some internal parts have different part numbers, most notably the shaft.
Hollander interchange says 49 and 50 are the same, and 51-55 are the same. But my Mallory dualpoint listing groups 1950-1959 together as their p/n YC250
49 and 50 303 used the Rochester AA back draft carb that needed a lower profile distributor cap to clear the huge crossways design air cleaner setup. The shorty 49-50 cap would have a shorter shaft (at the rotor end) compared to the later 51-up tall cap shaft, so that should explain the different part numbers that you found. yes it will fit into the later engines: I used an old chromed 49/50 dist on the 1955 324 because it also has the Edmunds dual Roch AA manifold and special Edmunds air cleaners that need the shortest distributor cap. That earlier dist fits the 324 just fine. As I recall, the early hold down clamp is different, due to it having a timing degree scale mounted at the dist base. I do know I had to drill/tap one or 2 holes for that degree scale hold down. I don't recall if you can eliminate that "degree scale hold down" to be able to use the 51-up hold down clamp.( I used the scaled one as it was also old chrome).
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