Steve,
The main pictures I have used for referance come from the following books:
Ford GT Then and Now - Adrian Streather - P206 shows a picture of 1012 at Daytona 1966 - this is before the rear deck snorkels were used and shows ducting from side intake (bottom 1/3rd of top intake) moulded into rear clip coming to a downward facing pipe on inside of rear wheel arch.
Ford GT40 The Legend Lives On - John Allen - P76 shows 1031 at 1966 Le Mans and shows how duct from rear deck snorkel connects into duct from side intake.
The Ford that beat Ferrari - Gordon Jones/John Allen - P130 shows 1012 in k11B form still with Y piece although duct to snorkels is disconnected as Shelby had removed from Mk11B at this time (although still fitted to H&M cars). - P113 has picture of 1031 in which you can just make out ducts.
P93 and P104 hve good pics of foam topped connector duct that leads to brakes.
Also see
1015 - Classic Le Mans 2006
Ford GT40 Mk II - Ultimatecarpage.com - Images, Specifications and Information
1016 - Classic Le Mans 2006
Ford GT40 Mk II - Ultimatecarpage.com - Images, Specifications and Information
1015 - 1966 Le Mans - you can just see rear clip duct
Ford GT40 Mark II - Supercars.net
Also there are a fair few oics scattered around on various forums showing how SPF MK11 clip is formed.
Dave