I can't help with the ID of the pumps (year or years of manufacture or "bump") but I do know that the first front mounted pumps made for the 37 block are basically interchangeable with all pumps through the last of the 59A production engines in 1948. Later 8RT truck pumps made from 48 through 52 will work on the older blocks but would normally only be used if you are converting to the conventional ignition distributor set up used on the 8BA, 8CM, or 8RT. You can also go the other way around and convert the later 8BA types to a crab cap distributor and use the early type pumps & fan set ups. This is what a lot of folks use when they are putting the later 8BA motors in an early configuration car or truck to get them to fit right. The crab type distributor is the best one made for the flatheads so this is a good way to go if front engine space is a problem. There is some concern about oiling of bushing type pumps though. Late 49 & on pumps had sealed bearings and didn't need engine oil lubrication but the early 49 back to 37 did. I think the early pumps can be converted for sealed bearings though and if thats the case, you wouldn't need the oil hole in the front of the block to oil the pump bushings.
Kerby
