Nascar Grand National 427 Identification, numbers, characteristics?????

This may sound like a dumb question, but i need a little help. A guy near where I live claims to have a 427 from a '65 Galaxie Nascar Grand National car. He claims he got it thru someone that got it from when the teams came out West during those years.

He says it was rebuilt in about '75 and has been sitting on his engine stand ever since.

My questions are:
Can a person possibly distinguish one of these engines from a stock 427?
If it was indeed a Nascar engine, should it have special parts?
Is there anything special about these engines?
Casting numbers?
Can I possibly tell from the outside of the engine if it was a racing engine or not?
Should it have Holman Moody casting numbers?
I would assume if it is the real deal, it would be worth more than a regular 427 (condition considered)???
I don't know how complete it is.
I have not seen it.
It might be just the block, shortblock, longblock, complete engine. I don't know.
Obviously, I don't want to spend extra money on something that isn't worth more than a garder variety 427.

He also mentioned he wiped out a '65 7 liter Gal in about '70 and still has some parts from it. That did make me think that maybe the engine he is trying to sell is the 427 stocker out of his '65.

Thanks for the help and time,
it is sincerely appreciated!
Steve Bava
norcal
bava17@aol.com
209-604-9461