gas tank venting

i am using a mustang gas tank with the filler neck in a 55 olds. if i use the stock gas cap and install a vent tube to outside the trunk will it vent out the cap or the vent tube? this might be a dumb ? but i am no genius and trying to save a dollar. any help is appreciated

 

If you vent the tank or the filler tube, you don't need a vented cap. If you vent the tank, be sure you put a roll-over valve at the end of the vent hose and have it mounted higher than the tank.

 

What kind of mods did you have to do to get the stang tank to fit?

 

If you have a non vented cap it will vent out the tube. If it is a vented cap the gas vapor will most likly go out the vent that has the least line pressure and that would be the vent tube.