81' Corvette Guy

Damn, I love my 25 gallon tank...woot!

WHITE 1974

Well did an idiot thing last night and ran out if gas 200 yards from the station across from my apartment. Walked to my underground got my gas can put in 9 liters walked to the car filled it, drove to the gas station and put in almost 59 more when I did the math that's 68 litres total converted to US gallons....almost exactly 18. I don't suggest trying this experiment but my tank definitely takes a full 18 gallons although it reads pretty close to empty at what would be 14 or 15 gallons. So there's the stupid way to prove a point. Lol

mrvette

My '72 vert has a 18 gallon tank, no rubber bladders of course....I know it'a a 18 gallon tank because I dropped it once, and when back together, I put in 5 gallons from a Red lawn tank....which was full up for the transfer....went to station not a mile away, and loaded another 13 gallons.....

now I take a wood stick and mark the fuel level to top of tank that has to be 18, then measure down 1/2 way since my tank is symmetrical and so that is obviously 9 gallons, 1/2 of that is obviously 4.5 gallons....guess from there....all this setting flat on the garage floor....

and yes, my tank reads funky but with aftermarket gauges......when it gets lo, I just use the wood for a good guess.....

ignatz

I never completely fill my tank anymore. Let me tell you my story, the short version.

Fill my car up one morning (69 small block), full load of nice cold gasoline. Drive home, short distance, car sits in the sun all day. I go to start it and it won't turn over. In fact the starter sounds kinda funny. After a lot of this and that I figure out that the motor is hydraulically locked. The gas expanded enough to push past my floats and fill a cylinder or two. I'm sure you've noticed that a full tank is pretty close to the level of the carb.

And yes I'd always believed my gas cap was vented. Seems that was not so. And happily I never got to the point where I'd actually got the motor cranking before I figured this out, because the oil was completely diluted with gasoline.

GrandSportC3

The gas gauge shows empty well before you are actually empty... The most that I've ever been able to fit into a tank was 17.5 gallons.. There was still a little bit of gas left when I filled it up... could have been 2.5 gallons.. So, 20 gallons seems right for my '68..

1975Coupe

This thread has been extremely helpful. I'm new to my 75 coupe and was also wondering how much fuel the tank holds. The most I've been able to get in her was 10 gallons. That's with the fuel gauge reading about 1/8th. So I guess it's being very loose with it's readings.

7T1vette

When new, the fuel gauge would read "E" when there was 2-3 gallons left in the tank. And, it would read above "F" when filled completely; maybe go a couple of gallons before the needle was aligned with "F".

Early C3 years had 18 gallon tanks. But aftermarket sending unit calibrations are poor, at best. If you are like me, you fill up when the gauge gets between 1/2 to 1/4 full. That way, you never risk running out of fuel and you don't get a lot of [internal] water condensation in the tank from just sitting.

jim in oregon

Frank, How 'bout you siphon all the gas in your tank, measure that..THEN IF it's clean reenter that amount and go get it filled up..? float to gauge may be imprecise..but I think yours is a 20 gallon tank..Jim

BTW Olsen BROS UP McLAUGHLIN BLVD in Milwaukie OR sells 92 octane ethanol free gas..Not cheap but better for the carbureted fuel systems..

Rescue Rogers

My 68 has a 15-16 gallon tank. Ive gotten more than 13 gallons in it when theres an inch or two left in the tank. Plus side, my gauge reads empty with a few gallons left and I'm currently getting about 16 mpg.