[chuckies76ta]

Hi: For those of you who have this on your 72 Firebird. The canister located behind the back seat. Have any of you remove it or did you connect the vent hoses up. I'm doing a restoration on a 72 and wondering what path to take. My 76 has noting like this and all I have ever used is a vented cap. Never had any issues. Even our 68 Firebird just uses a vented cap. Thoughts? Thanks.

[72projectbird]

My 71 has that. Nothing is hooked up to it, so it's not functional. I decided to leave it in place rather than remove it and patch the hole in the floor where it used to be.

[78w72]

My 72 had that EEC emission thing, I removed it and used a new non vented tank since I didnt want to run the lines and keep that, my other cars with the charcoal canister set up I eliminated too. Never had issues with vac/psi in the tank or smells when parked in the garage.

On the 72, i use a early style vented cap along with the Tanks Inc vent that has a rollover protection feature, installed as high up as possible mounted to a bracket on the frame or trunk floor near pass side. Some on here dont like the vents but others use them and they work great... i have zero fuel slosh or seepage with hard driving on the street or low 11s at the dragstrip and it did fix a slight vac issue i had at first since the cap only vents out, also no slosh or seepage using the aftermarket but OEM style cap.

[chuckies76ta]

Thank you guys for posting. I appreciate it. I will just eliminate it also...

[tom s]

From my experience,vented caps let air in but not escape!If it does not have a way to escape and hot weather can allow the fuel to build internal pressure,has to go somewhere so it can force fuel past the needle and seats in carbs,can fill a cylinder with fuel.Happened to me in my 69 bird with a irreplaceable RA V tunnel port engine.Was lucky,it locked up and did not fire and push a piston out the block.Took spark plugs out it shot raw gas over the fenders of the car.I had a spare cap I drilled a small hole in when the car was not being driven.FWIW,Tom

[chuckies76ta]

Thanks Tom, I'm gonna do the vented cap and connect one of the vents on the tank to a check style vent with filter of some sort. Maybe something like this https://www.amazon.com/EVIL-ENERGY-R...085G7JVSM?th=1

[78w72]

Originally Posted by tom s

From my experience,vented caps let air in but not escape!If it does not have a way to escape and hot weather can allow the fuel to build internal pressure,has to go somewhere so it can force fuel past the needle and seats in carbs,can fill a cylinder with fuel.Happened to me in my 69 bird with a irreplaceable RA V tunnel port engine.Was lucky,it locked up and did not fire and push a piston out the block.Took spark plugs out it shot raw gas over the fenders of the car.I had a spare cap I drilled a small hole in when the car was not being driven.FWIW,Tom

Thanks for clarification, i was thinking backwards... the vented cap allows air in to compensate for fuel being sucked out but doesnt allow air out to relieve pressure, thats what the added vent does.

https://www.tanksinc.com/index.cfm/p...iABEgJkUfD_BwE

[72projectbird]

Originally Posted by tom s

From my experience,vented caps let air in but not escape!If it does not have a way to escape and hot weather can allow the fuel to build internal pressure,has to go somewhere so it can force fuel past the needle and seats in carbs,can fill a cylinder with fuel.Happened to me in my 69 bird with a irreplaceable RA V tunnel port engine.Was lucky,it locked up and did not fire and push a piston out the block.Took spark plugs out it shot raw gas over the fenders of the car.I had a spare cap I drilled a small hole in when the car was not being driven.FWIW,Tom

Had the same happen. Filled the crankcase with almost 2 gallons of fuel.