Like always, if it's too good to be true, it usually is.
I called this guy and talked to him at length. I had him under the car, in front of the engine...everywhere.
I first had him check to see if it's a S/O...it didn't have pipe plug on the front of the block to the driver's side of the timing cover. So it's not a S/O.
I then had him check to see if it was a C/O....it didn't have cross bolted mains and it didn't have screw in freeze plugs either. So that eliminated the possibilities of a 427 C/O and a 406.
There were a lot of 352's and 390's made....I'd say that's what it is.
If it was a S/O, I was going after it this evening.