I have received a new tank for the 48 and it has a vent spout.Can I plug it with out creating a vacumn???No vent on the old tank and I am useing a stock cap,chef

The vent pipe next to or connected to the top of the filler neck is to allow air to escape from the tank while its being filled. Not all tanks required this feature and the 1941-48 did not have it. They were one car that should have had it because if you fill the tank too fast the gas will blow back out. First I would check to see if its the correct tank and not a 1950-52 tank. Probably a good idea to contact the place you bought it from. Either way the vented cap was used and the vent in the cap it to allow air to enter the tank and the gas departs.

Gene is correct filling too fast will cause the gas to spill out the fill pipe. I found the best solution for that is the accessory fill tank alarm. Since In installed one in my 48 I have not overfilled the tank. The alarm makes a loud whistle sound until the tank is full then the whistle stops. When it stops, stop pumping gas. A very easy accessory to install. It does draw attention at the gas station !

That feature was standard equipment on 1950-52 Chevrolet cars.

Heres what ya need chef! I have one installed on my 47, and it works GREAT! It does gather attention at gas stations though.


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The new tank is almost identical to the old one except no drain hole in the middle bottom and an addition of the vent tube which is next to the filler pipe location (outside the tank) the tube is about 2 inches long and it apears it should accept a rubber hose and the instructions say to run it up above the tank and then back down and hide some where in the body??My fear would be the fumes that would escape if left open to breathe,Thoughts,Chef

With the stock original setup it is vent through the gas cap so fumes are always escaping. I don't know their reasoning but I would place a hose on it (gas resistant hose) and install the tank. You can vent it as mentioned or for an experiment you could pinch off the hose and see if a vacuum developes when fuel is used from the tank. If a vaccum developes you will hear a hiss when the cap is loosened. If the hose left open and used the tank could be filled at a faster rate and not blow back gas then the normal slow rate the 1948 usually requires.

I am planning on going with the whistle and plug the hole.chef