It's an 8V Tunnel Port as noted in a different article than the pic shown below. You can see the dual Holleys though through the clear Plexiglass air box.
http://www.supercars.net/Pics?v=y&id=694&s=c&p=1967_Ford_GT40MarkIV22.jpgPast articles also mentioned that it was a virtual copy of the NASCAR engine but slightly detuned. Not sure how but I'll guess it was with a lower C/R as under FIA rules, all entrants had to run the same French-supplied gas which I'll again venture wasn't the same 103+ octane leaded race gas NASCAR used (Pure was the USA supplier then, who did the French gas is up for a guess!). And yes, 427's used in '66 races showed a need for heavier rods, hence the LeMan's rod was developed.
Interesting factoid. Gurney and Foyt drove #1 to victory and in the winner's circle, as was the practice for years, the drivers were given a large bottle of champagne.....to drink. Gurney instead shook it up and sprayed the crowd, Henry Ford II, but especially the press pool reporters who said pre-race that the duo could not win and would fight each other instead. Hence, he was the forerunner of this spray-the-bubbly practice that continues to this day.
"This win came just a week after his surprise victory with A.J. Foyt at 24 hours of Le Mans, where Gurney spontaneously began the now-familiar winner's tradition of spraying champagne from the podium to celebrate the unexpected win against the Ferraris and the other Ford GT40 teams. Gurney said later that he took great satisfaction in proving wrong the critics (including some members of the Ford team) who predicted the two great drivers, normally rivals, would break their car in an effort to show each other up." Wikipedia.