Gas tank question
Thread Starter
Instructor
Joined: Jun 2025
Posts: 155
Likes: 156
From: NH
Gas tank question
Been meaning to ask for a while, but have general question with regard to my C3 gas tank. Still relatively new to vette ownership , and when I bought this one it had previously been restored. The gas tank doesn't have a the flap, etc inside the fill pipe that I am used to on vehicles I have always owned. It is like filling ajerry can. I can look straight into the tank. Don't really even need agas gauge, I can visually check the depth of fuel level. My question is whether this is a normal configuration?
Racer
Joined: Sep 2017
Posts: 334
Likes: 56
Hello. That is normal up to 74, no flap or restriction just a wide opening. Not the greatest for enviroment or even the health of the person filling it up but that the way it was.
You can look at the vendors sites and their catalogues and it will show parts and how they fit and look. Take care.
You can look at the vendors sites and their catalogues and it will show parts and how they fit and look. Take care.
Thread Starter
Instructor
Joined: Jun 2025
Posts: 155
Likes: 156
From: NH
Hello. That is normal up to 74, no flap or restriction just a wide opening. Not the greatest for enviroment or even the health of the person filling it up but that the way it was.
You can look at the vendors sites and their catalogues and it will show parts and how they fit and look. Take care.
You can look at the vendors sites and their catalogues and it will show parts and how they fit and look. Take care.
Last edited by majorbob; Dec 20, 2025 at 12:27 PM.
Burning Brakes
Joined: Sep 2020
Posts: 796
Likes: 794
From: Chapin SC 29036
The large opening for the tank also has some benefits.
One is that you can physically see how much gas you have.
When I bought my car it has some water in the tank, so I siphoned it out and then carefully got my hand into the tank and wiped up any remaining liquid.
The float on my gas gauge had come off and was floating in the tank and I was able to reach inside and get the float and reinstall it from the top.
Getting my hand into the tank wasn't too hard, but getting it back out was not so much fun. The metal hole is smooth going in, but the bottom of that tube was kind of sharp. Would have been easier if my hand was a little smaller.
You can't let go of the gas nozzle while you are putting gas in, but that really isn't a big deal.
One is that you can physically see how much gas you have.
When I bought my car it has some water in the tank, so I siphoned it out and then carefully got my hand into the tank and wiped up any remaining liquid.
The float on my gas gauge had come off and was floating in the tank and I was able to reach inside and get the float and reinstall it from the top.
Getting my hand into the tank wasn't too hard, but getting it back out was not so much fun. The metal hole is smooth going in, but the bottom of that tube was kind of sharp. Would have been easier if my hand was a little smaller.
You can't let go of the gas nozzle while you are putting gas in, but that really isn't a big deal.
Thread Starter
Instructor
Joined: Jun 2025
Posts: 155
Likes: 156
From: NH
The large opening for the tank also has some benefits.
One is that you can physically see how much gas you have.
When I bought my car it has some water in the tank, so I siphoned it out and then carefully got my hand into the tank and wiped up any remaining liquid.
The float on my gas gauge had come off and was floating in the tank and I was able to reach inside and get the float and reinstall it from the top.
Getting my hand into the tank wasn't too hard, but getting it back out was not so much fun. The metal hole is smooth going in, but the bottom of that tube was kind of sharp. Would have been easier if my hand was a little smaller.
You can't let go of the gas nozzle while you are putting gas in, but that really isn't a big deal.
One is that you can physically see how much gas you have.
When I bought my car it has some water in the tank, so I siphoned it out and then carefully got my hand into the tank and wiped up any remaining liquid.
The float on my gas gauge had come off and was floating in the tank and I was able to reach inside and get the float and reinstall it from the top.
Getting my hand into the tank wasn't too hard, but getting it back out was not so much fun. The metal hole is smooth going in, but the bottom of that tube was kind of sharp. Would have been easier if my hand was a little smaller.
You can't let go of the gas nozzle while you are putting gas in, but that really isn't a big deal.
Team Owner
Joined: Sep 2006
Posts: 31,168
Likes: 4,245
From: Westminster Maryland
Hello,
Since the float sits on the surface of the gas in the tank the gauge fluctuates some as the gas sloshes in the tank.
The gauge has a bit of a delay though so the needle should not be moving continuously.
Normally only when the tank is at a steep angle.
Is the float at the surface?
Regards...
Since the float sits on the surface of the gas in the tank the gauge fluctuates some as the gas sloshes in the tank.
The gauge has a bit of a delay though so the needle should not be moving continuously.
Normally only when the tank is at a steep angle.
Is the float at the surface?
Regards...
Last edited by Alan 71; Dec 21, 2025 at 09:05 AM.
Le Mans Master
Joined: Jan 2007
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From: Omaha NE
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1967 Pedal Car Champion
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From: US-PNW
Rabbit trail question:
The wide filler hole first appeared on the '63 Corvettes. I assume it was a "race/performance" feature for quick-fill cans. Did any other production cars have this?
(not sure I consider AC Cobras as production cars, but I believe they also had this feature)
The wide filler hole first appeared on the '63 Corvettes. I assume it was a "race/performance" feature for quick-fill cans. Did any other production cars have this?
(not sure I consider AC Cobras as production cars, but I believe they also had this feature)
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Team Owner
Joined: Sep 2006
Posts: 31,168
Likes: 4,245
From: Westminster Maryland
Hello bro,
Could this have have something to do with the position of the filler?
The filler was above the tank while on many/most cars of that era the filler was either on the side or rear of the tank.
The tank was mounted high on Corvettes compared to other cars
Regards....
Didn't the size of the neck really have to do with only being able to pump unleaded into new cars?
Could this have have something to do with the position of the filler?
The filler was above the tank while on many/most cars of that era the filler was either on the side or rear of the tank.
The tank was mounted high on Corvettes compared to other cars
Regards....
Didn't the size of the neck really have to do with only being able to pump unleaded into new cars?
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
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Cruise-In VIII Veteran
When they went to unleaded. The size of the pipe never changed. They installed the flapper about 3 inches in with a reduced sized hole thus choking it down so the leaded nossle which was fatter wouldn't fit.
we used to punch em out back in the 70's, early 80's.
My 77 has it's factory flapper punched out. Been that way since the 70's.
we used to punch em out back in the 70's, early 80's.
My 77 has it's factory flapper punched out. Been that way since the 70's.
Thread Starter
Instructor
Joined: Jun 2025
Posts: 155
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From: NH
My first car, and thus the start of my experience with gas tanks, was a 76 Mustang II. Basically a notchback pinto with pony badges. Had 4 bangs and a wimper. Didn't matter what gas you put in it, it wasn't running fast
Le Mans Master
Joined: Jan 2007
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From: Omaha NE
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..
Thread Starter
Instructor
Joined: Jun 2025
Posts: 155
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From: NH
