I had a '68 Belvedere 4 door in that same color. 318/904 no power steering.
I agree with the above post, if you leave it as is, or just freshen it up, that car would get a lot of attention as a survivor. Is she stripped? Radio? any options?
I would leave it as is - way better. too many clone police cars. there are like General Lees now. and dont really pul any more dollars. Police car collectors want accuracy and most clones dont come close. If you dont like it the way it is Id sell it - survivors are scarce and this is one uniquely interesting car.