Horray! Took the Dak back out to the Ram Off Road Park for its last-and-final heat-soak test, and the newly re-designed fuel system passed with flying colors - no fuel system/pressure/vapor-locking issues at all 👍 .

The surge tank is now located under the bed -



So, the main tank supplies low-pressure fuel to a surge tank, and the surge tank contains the fuel for the high-pressure EFI system. The main tank supplies fuel to the surge tank via a basic low-pressure 4.5 gph/30 psi fuel pump, and that return side now has a simple but very effective 'sight gauge' (a 5/16 fuel filter), which...if it's full then so is the surge tank, which is exactly what I want. If it's not full then neither is the surge tank, and that's bad, so the little fuel filter is my quick-visual-reference to ensure 'all is well'. The angle with the below pic is without the shield in place to protect the surge tank and plumbing from rocks and road debris, and I can 'peek' at the filter between the cab and bed - works awesome.



All the fuel lines are now 5/16". The two high-pressure fuel lines are now the only fuel lines going up into the engine bay, and both lines are double insulated - first with DEI 3/8 Vapor Lock insulation wrap, and then again with 1/2 heat sleeve, all secured in place with clamps and plastic blocks to keep the lines away from the frame and firewall (a black cutting board works great for making 'spacers', btw) -