Here’s a 289 engine for sale with date code December 14, 1964. Price is $150. I saw this on Facebook marketplace today and the guy responded with a picture of the date code.
There are plenty of websites that list the date codes for these. Such as Mustangtek http://mustangtek.com/FordDecode.html#Table21
This block decodes as being built December 14, 1964. That’s the 4M14. 4=1964, M=December and 14 is the day of month. The next row starts with C5AE. C=1960’s. 5 would normally mean 1965 but the date code over rules. A=generic. If it were a Z instead of A it would definitely mean Mustang. But I think during 1964 the Mustang was so popular that Ford was grabbing any engine they could. So the A may be legit for a Mustang. E=engine. The 6015E means it is a 289 block built in the E plant. Check out this website https://www.fastbackstack.com/2007/06/how-to-decode-your-1965-1970-mustang-engine-block-number/ that shows us the engine date code should be about 2-6 week before your car build date. So a Mustang built in January 1965 would be perfect for this block. If I owned a Mustang with a January 1965 date I’d buy this block just to store and sell with the car later.
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