There were overall new publications to the Master Parts Books and annual addendums. The 1965 an 1969 Master Parts Books are complete new publications but I have addendums for 1966, 1967, and 1968. There were of course MPB's before and after.
- The first version I bought 20 years ago was the 1969 MPB. It is a good set to have and for a parts seller like me shows what parts continued to be use on years after 1964.
-I then bought the 1966, 67, 68 revisions. Those are good to see the progression of parts, and sometimes they had different illustrations and information that had been deleted, or replaced by newer parts by 1969.
For example if I see one part number in the 1965 MPB and then a different one in 1969, I will sometimes go thru each year and see perhaps when it changed. That tells me exactly when that part was superseded and replaced by a new part.
- To me the 1965 Master Parts book is the Bible as it was closest to our 63/64 model years and is most likely to have the original part and part number. It will often have history as you will often have notes indicating to sell the old part # then use the new part #.
As an example I like to use horns. The 63 Hi & Lo Note conch shell shaped horns were physically bigger than the 1964 and later horns, although they are physically interchangeable.
In the 1965 MPB entry for those horns below you will note that it states
Hi Note: 1957-60, 1963 use part # 900-0444 until exhausted then use part # 900-514.
Lo Note: 1961-63 use part # 900-0429 until exhausted then use part # 900-513.
If you go to the 1969 MPB it simply says use part # 900-514 for all 1953 to 1969 Cadillacs for the Hi Note horn.
If you look at the Lo Note horn in the 1969 MPB, they are actually listing a 3rd part # (900-0239). This where I would pull the 1966, 67, 68 addendums and see where it changed. Since 1966 still lists 900-513, nd 1967 lists the new 3rd # 900-0239, then the 2nd replacement occurred around 1966/67.
The point being is that the part numbers changed year to year and sometimes the parts physically changed (e.g. 64 and later horns smaller than the prior horns) or the numbers sometimes just changed with no particular change observed.
I believe most digital forms of the Master Parts Book on CD includes a 1950, 1958, 1965, and 1974 Master Book Version, and that 1965 version is the one I go to to get the most accurate information on what was actually used on a car, but if someone say has a 1968 Cadillac and wants to know if a particular part from a 63/64 I have parted out will work, I will often turn to the 1969 version or the addendums. I believe I have only seen the 1969 version as a print copy.
Just one final note on Master Parts Books: They changed the parts number structure including Group Numbers and Part #'s, I believe in 1964. If you get a 1964 MPB Addendum you would see references to the old numbers as I recall. Any older MPB's of course only have these older parts #'s. You will see the old parts group in parenthesis below in the 1965 MPB Entry.
965 Master Parts Book Entry for Horns:
The 69 MPB will be better for interchange information. The 74 and later will provide even more information on some parts but you will see that some of the 64 and earlier parts are not even listed at this point (ie. no replacement). The 65 MPB will be more helpful if restoring to original. The best of both worlds is to have both 65 and 69 editions. Keep in mind if you are restoring to original and just install anything Cadillacs sold as a replacement in the years and decades following, you can end up with a “Johnny Cash Cadillac”. But, if you are just trying to get the car running and functional part numbers and physical style changes will not matter and the latter MPB’s can be very helpful.
Just to add, in the 70's they went to two manuals: a Master Parts and Accessories Catalog with a straight listing of parts, and a Parts & Accessories Illustrations and General Information Catalog with all the basic info such as Parts Number System Explanation, VIN Info, body plate info, body style charts by years, capacity charts, tire size charts, interior charts, paint code charts, etc., etc. and then the Part Illustration in subsequent chapter.
With my digital set of MPBs, I received the 1974 Master Parts Catalog and the 1973 Illustrations and General Information Catalog. It also included the 1950, 1958, and 1965 Master Parts Catalogs. They come on a CD and re a simple PDF file which you can copy to your PC, Laptop or mobile device. They are searchable PDF files so you can often find things much faster than thumbing through the 1000 page paper MPBs. Often, if I need a clean illustration I will find the item in digital form then go to my paper original Master Parts Book.