When it comes to those engines, the heads bolted on the block are all that matters. Not sure how original the owner is claiming the thing is but the only thing I would be doing is opening the valve covers to know which heads it has. That old and it could be anything and people bolt large round port heads on Peanut ports all of the time. Peanut port, round port, square port... All of that matters if you are considering it for power of any kind. My jet boat 454 was a 320 hp tiny peanut port, open chamber, low performance baby when I got it. Now it has square port, closed chamber heads with 2.30" intake valves. Higher compression and massive flow numbers. What is your plans for it?