I have A 68 f250 with two gas tanks .Are the gas caps vented or not?

 

Originally I believe that the tanks were vented but not the caps.

 

’67 – ’69 tanks use a vented cap, ’70 – ’72 tanks use a nonvented cap.

 

my 68 F100 has vented tank on the inside not for sure about the second one but IM sure it is too. The caps on mine are not vented but it has stock tank venting if you have the one behind the seat it looks kinda like a loop!

 

Steve, is your tank original? Reason I ask is because the closed system with the vented tanks came out in ’70 along with vapor recovery and charcoal canisters, same deal for all the cars and vans too. That’s why the later tanks hold less gas, to make more room for the vapor separator on top. I just went back out to the parking lot to double-check my ’68 and it has only one line coming out that goes to the motor, same thing for the auxiliary tank. Where is this loop on yours?

Barry