This interesting bit of trivia was posted by Steven B. in the Fordson Discussion Forum. It pertains to engine parts made by the Ford Motor Company, including tractor parts.

"Replaced by" means the part was superseded. All of my part books date back to 1964 and New Holland have changed some part numbers. They usually put the old Ford part number on the package.

I was suppressed when I looked up the part number of the auxiliary drive shaft because for some reason the part number went through a radical change and it lost its "Basic Part Number".

Ford part numbers follow the following rules. Most part numbers are in three parts. The middle part is called the "Basic Part Number". If you look in a parts book for the crankshaft of a 1969 Boss 427 Mustang, the "Basic Part Number" is the same as the crankshaft for your tractor. What identifies the part from other crankshafts is the Prefix and the Suffix. So, as the crankshaft in a Fordson Super Major Diesel is the same as the gas or kero engine, all parts that are common to all three will have the prefix "E1ADN". If the part is diesel specific it will have the prefix "E1ADDN". The suffix is the revision. A number that goes "E1ADDN 12345 B" would be the second revision.

The prefix’s are country specific. In the US, the prefix tells you the year, model and type. E.g. D1ZZ 1234 A would be a part from a 1971 performance car. A=1940, B=1950 etc. 1=first year of decade, Z = performance. Truck parts =T, US tractors I am not sure of, but I think it is the same as the UK =N. E1ADDN = England, 1=1951, AD= model, D=Diesel, N= Tractor.

Now, there are some parts that do not fit the "Basic Part Number" scheme. These parts are numbered in numerical order with prefixes and suffixes that denote country of origin, group (engine, gearbox etc) and vehicle type.

This information is useful when you are searching obsolete parts and often you can find parts from other applications. Also note, the Fordson engine was used in trucks. The piston rings that you buy from New Holland will have the prefix 510E, this is the six cylinder version of the truck engine and it got a Truck prefix instead of a tractor, but it was used in the tractors and replaced a previous part number that would have had the E1ADDN prefix.