Soooo confused!!!!!!

[kecah04]

Here's a confounding riddle.
I am looking into putting a "new" engine in my '70 c-10.

My dad pulled an engine out of a rearended Impala. I don't know what year it was. anyway. I got the block numbers so I could find out just what we have here. Here's the riddle. the Back number is 3932386, which checks out as:
3932386....302.....69....4...Z-28 Camaro
3932386....327.....69....2
3932386....350.....69....4

Now the front number suffix is HV.

this checks out as:
1965 HV 327 h/p, hyd lif, t/ig, m/t 350 4 Vette

How can a block manufactured in 69 have a suffix stamp that says it was installed in a 65 Vette?

Any guesses? I don't have the answer. Help!!!