ventilation verification for gas tank

[64_twins]

I installed an LMC gas tank a while back and am just now getting ready for the road. I capped off the vents from the tank. Actually they came capped off. Anyway I ran the overflow line from the filler, the filler hose and the gas line but I'm curious about venting. I read alot of threads on the newer models where there was a carbon filter,etc... I don't believe the original tank is vented? I have a late model Tahoe filler cap and tube installed in the side of my fender. Sorry no pics. Can someonje tell me if I'm going to have any problems with this when I hit the road? It rides around the yard no problems but it sure pops alot during the day.

[markeb01]

All tanks must be vented either to the atmosphere or as part of a fuel recycle system. Incoming air must replace the volume of fuel being used. If there is no vent, eventually the engine will starve for fuel, and the tank may collapse from internal vacuum.

Up until smog controls came into play, most tanks were vented by the filler lid - a "vented cap". This is part of why these trucks always smell like gas especially on a hot day with a full tank. Later caps are non-vented (sealed) requiring a separate vent.

I installed a Rock Valley tank on my 1960 and used one of their check ball vents with a sealed aircraft filler cap. The following link shows the check ball vent #119-1810 (I'm sure there are other brands as well):

http://www.rockvalleyantiqueautopart...-conn_hose.pdf

They allow air in the tank but will close off in the rig rolls over. I mounted my vent valve at the highest point under the stepside rear fender. There's a hose running to it from the tank vent outlet, and another hose running to above the rear axle for incoming air. If you run a carbon filter it would be installed where the air enters the system. Good luck.

[64_twins]

Thanks. Just to make sure I am clear on the best way to avoid problems. There are three additional ports on my tank besides the filler. I hooked a hose from my filler neck to one of the ports as I thought that might be for overflow. On the other two. Should I put a check valve on each one or just one of them? If only one should I cap the other off or put a different type valve on it for when I'm adding fuel?