Working on a body swapped k10 using a tahoe frame and factory 2000 tahoe fuel tank. I relocated the filler neck to bedside, hidden in the stakepocket. I am trying to determine if I need to have a vent at the filler neck like the factory filler neck had before. My assumption is that I need it in order for the tank to fill properly? Otherwise, it would likely take quite awhile for the tank to fill. The issue is that I have no extra room to add this vent line at the filler neck due to limited space in the stakepocket. I am wondering how necessary it really is? In California, the nozzles require you to have the boot/seal of the nozzle fully deprtessed against the filler. However, if you pull back the boot of the nozzle when filling, it allows you to pump gas and would create a way for the tank to vent while filling. I know this is a hassle, but I am not too worried - this is a project vehicle that will hadly get driven (hidden gas filler is for looks, not functionality).

The gas cap I purchased states that it is a vented cap. I am pretty sure the factory trucks use vented caps as well, so that should take care of the tank being able to vent under operation, correct?

I also thought of an alternate solution for the filler neck vent pictured below. The picture shows the vent stubbing up off the horizontal part of the filler pipe (rather than the vertical part). The problem I see with this is that it is too far away from where the nozzle is insterted. Do you think this might work?

 

My Dad found out the hard way on his 1964 GMC that if you just use the cap as your only vent it causes problems. He filled up, parked in the sun, and the hot gas puked out the cap onto his paint. Had to repaint and blend everything on the side of the truck near the gas cap, since he uses it as a show truck. You really need a vent high up on the neck and an overflow tube going somewhere that gas will not damage.

 

Got it, that is good info. However, the truck (when it was a tahoe before the body swap) never had this issue, so technically I am retaining the factory setup. You still bring up a good point though - I definetly do not want fuel puking all over the paint. As an extra precaution, the tank itself could always be vented via drilling and tapping the top of the tank, correct? If so, where would I run this vent to? Open air (like a diff breather)?

 

On a couple of my LS swaps I used Tanks Inc EFI gas tanks They supply with the tank a tiny cone filter that looks like cone air filter. I just ran a 3/8"? fuel line up and away to a high point. Never had a issue with gas pushing out. Sorry no pics.

 

Got it, so it is basically just like a differential or trans breather hose? No issues with gas smell or anything like that? Seems like the simplest way to vent since the vented caps (even factory ones) seem to sometimes go bad.

 

My 80 Camaro LS 6.2 swap with a Tank's Inc tank is sitting right next to me in the shop. Zero gas smell issues.
Just thought of this. Because I am old LOL I don't remember if Tank's includes a roll over valve to go in the vent line. The roll over valve goes in-line in the vent line. It's open unless your hot rod is on the roof keeping the gas from pouring out of the vent in case of a roll over.

 

Always provide a venting system designed to not dump fuel in case of upside-down-ness. Tanks Inc. has a rollover valve or you can vent the top of the tank or filler neck and run the vent DOWN under the tank. There may be some fuel smell after a few days stored in the garage but one way or the other (without running the vent thru a charcoal canister) the tank is open to the air.