TR6 engine numbers

[Bandre Frank Contractor AMC/SCP <Frank.Bandre@scott.af.mil>]

To all

Anyone know of a reference as to build dates of engines based on their
number?  References I have seen in the past say that the commissioning
number and engine number should be close, but my 76 TR6 (CF57005U) has an
engine number of CF47004U.  Should I suspect a different engine has been put
into my car?

Frank