Using my mad google skillz I discovered mr. wpfontenot has recently purchased several Ford 460 parts on ebay. So I would say that's a 460 block there. It's hard to say how many CI he's at tho, but if I was going through the trouble of installing a 460 in a fox I would bore and stroke it out to 514+.
Why stop at 514? I've seen a BBF stroker kit as big as 605ci. That thing would be an all out animal with heads and an intake that could support that many cubes.
....I haven't done my homework on big blocks so I don't know how big you can go. 605ci would be pretty fun

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Where did he get those smaller engine stands?