Not being a total expert on these matters, I would hesitate to add that all 1966 Le Mans GT40s, whether they were MkIs or MkIIs, had a single filler cross over system. I believe the pipe was either in front of the seats or under them, which meant serious adjustment to that part of the monocoque. I only know this because my MkI, the bodywork off which did Le Mans that year had the single filler on the right hand side. I believe this was a ruling at the time. I guess because the pit crews would be stationed on the right of the car, not on the left, which would result in them having to refuel next to the open track.. no concrete pits wall in those days. Surely not health & safety in 1966???.. Andrew