Cadillac 331 engines

[Fleetwood Meadow]

I have 2 ‘52 Cadillac Series 75s. 1 is a parts car and the other is in pretty decent shape, as it is shown in the restoration projects section of this site. I’m not overly knowledged on the history of GMs engines but 1 thing stood out when looking at both of the engines. Instead of saying 5275XXX like the book says they should, they both say 5360XXX. Based on those numbers that means both engines came from ‘53 Series 60s. Correct me if I’m wrong on that. 1 car came from Washington state and the other from Pennsylvania. Was there something wrong with the ‘52 331s that would cause them to both be replaced with an engine from the next year? Was this a common practice in cars? 

Edited February 9, 2019 by Meadowfleet
Misspelled word (see edit history)

[JoeShmoe]

While researching casting numbers a while back, I ran into something that may be relevant. In at least one (1953?, 1955?) of the Cadillac Master Parts Books, it was noted that there were 2 different part numbers for each entire head assembly. The earlier number was to be replaced by the later but only in pairs. Later parts books only show the later number.  I believe the earlier version was prone to cracking. I wouldn't be surprised if the entire engines were warranty or recall replacements.   ....Joe