When you talk to him next, tell him there is a guy in Rowan County who has a business dealing with W-engines (348-409). As far as I remember they are a complete W engine shop selling cores to complete engines, and even do machine work to these blocks, which I've been told is a little complicated and you really need to know what you're doing with a 348-409. I've been looking for a reasonable 409 block myself and stumbled across him at a show a year or two ago. I can't remember the business name right now, but I have his card around here somewhere. If I find it I let you know.
Also, I have some numbers books that should cover that car if he would like to know what the car was originally built with and where. I'd just need the numbers/trim tag.