Can't be of much help - haven't found an original untouched 70 Evap Shelby to put up on the rack and take a bunch of pictures yet
Not sure if they used a system the same as the Mustang - which would require two lines - divided at the passenger rear frame rail for the valve or something else
Can offer currently only the front start of the solid line - attaches to the top of the charcoal canister goes back to the firewall then down the driveline tunnel to the back of the car
And a picture of the line following the rear frame rail (wheel side) at the drivers side rear to the flex line and into the trunk area
Checked and tried. - SAAC site might turn up and owner or two that might provide some additional pictures