Plug wire routing

[DMXF]

Bob - I don't want to beat this to death, but just for clarification here is a typical GT40 427 engine. Note how there is plenty of room to run the wires over the top of the valve covers, as in other GT configurations:

The primary reason for running the wires around the side was, I understand, to aid accessibility for maintenance (ie; ease in removing valve covers for rocker adjustments, etc), which was just an evolutionary manifestation of Ford's GT effort and would likely not have been unique to just the GT40 had the big block Cobra works effort gone forward. Again, the lightweight MR engines that SA would have been able to purchase from Ford in '66 for Cobras it would appear had the around the side wires (one of these days when I have time I'll dig out those build sheets to verify what is shown for plug wires).

Also, this image of P1057 shows an airbox that is similar to what is pictured in one of the early Cobra 427 homologation documents with the webers.
Running wires around the sides of the valve covers for this would be highly likely, also based on how SA incorporated a hybrid around the side, but clip on the valve cover wire routing for the Daytona Coupes. Even without an airbox it's also not a great idea to have ignition wires up against or very close to the side of carburetors in the event of breakdown in the wire shielding and inadvertent arc (more common than you might think) jumping to the carb.