In looking for information on an accessory I came across this:
http://vcca.org/forum/ubbthreads.php/topics/119044/1
pdxjoe said "On page 18 of my '48 accessory manual is the GAS TANK SIGNAL. It has a picture of someone filling the tank and the plumbing of the device. "The new signal ventilates the gas tank, avoiding waste and insuring fast filling, and provides an anti-siphon baffle for gasoline protection. Easily installed in only a few minutes time".
does anyone have this '48 accessory manual could you post a picture of this device.
thanks in advance, Bill

Bill - try this site for a pic of the signal..I have one installed on my 48. I would not be without, it really saves the fender and money on spilled gas.

http://www.1948chevy.com/images-acc/gas-sig.jpg

Hope this helps you .

I have one on my 47. One of the more useful accessories!

I have one on my 48 and it does keep you from splashing fuel all over the place......and it's fun watching other people at the gas station when you're filling up.

I recall from my "filling station" days the 1941-1948 cars could not be filled at full pump flow. If you did the fuel would blow back at you. The only thing the whistle would do is stop whistelingwhen you were almost full. The whistle was still an accessory in 1949 and standard equipement from 1950-1952.
If the gas overflowed on a 1949 some would seep down the outside of the filler neck and get into the trunk. The 1950 had an oversized opening around the filler neck so the gas would run onto the ground below and not into the trunk.
The whistle was part of the taxi equipment in 1949.

thanks so much for the photo. I never guessed this device would be so huge. I've been trying to figure out to recreate the one in my 1950 styleline which I threw away when I installed a new steel tank. I was able to come up with the basic design from people on ChevyTalk but this is not an easy task due to the vent line being permanently attached to my new tank.
http://www.chevytalk.org/fusionbb/showtopic.php?tid/236657/
thanks again, Bill