I just pulled the engine block casting # off my 1969 Mach 1 and it reads:
C90E-6015-B

and the date stamp is 9K28

I know how to decipher the date (Nov. 28, 1969), but is the casting # correct for a 351W? Anyone?

If so, is it safe to assume that at some point the engine was changed out for a 351w from a later vehicle? My car's production date is 9/9/68, which is over a year prior to the engine block casting date.

 

yep ,nice 69er though. looks like original engine better keep her in good shape

 

period correct parts are good if you enter contests...otherwise, just nice to have but not necesary, IMO.
restomod vs. show car