full tank of gas

[Raider L]

I hear a lot about how much fuel tanks for C10's are but I've never heard anyone say they had a tank the size I have in my '74 C10. I hear 16 gal., and 20 gal. but my tank is 18.5 gals. I know for a fact it is because I've filled it up from bone dry. What other trucks have tanks that big? Do 454 engines have tank sizes larger than 16? Does the engine size matter? I know that Blazers have really big tanks, but how are they plumbed? Do you think I got a Blazer tank in my truck but turned sideways? I know that sounds ridiculous but if the hoses would match up and they had it laying there, why not? Are there other trucks that have some tank size other than 16 and 20gal. sizes?

My truck seems to be made up of all kinds of parts not light duty C10, like the leaf springs are K10 leaf springs, from the factory. Unless that old man up in Mena, Ark. the one owner I bought it from, ordered it that way, but otherwise it's an ordinary C10. Like it has a half a Z28 engine in it from the factory (I later made a whole real Z28 engine out of it), you know that man didn't tell them, "Hey if you find half a Z28 engine laying around, pop it in there for me." when he possibly ordered it? So, I don't think he ordered anything. He went to the lot and bought it, like it was all morphed up.

 

[Turbo4whl]

Back in the 1970's, dealers made a better profit on the factory options. So many would add some to their dealer stock. Heavy duty rear springs, HD radiator, power steering and brakes to name a few. Appearance packages would add a lot so not every truck was ordered fully loaded. AC and tinted glass were also options as well as the rear bumpers on pickups.

This also allowed the dealer to mark down the list price more, that way they could compete with other dealers.

In 1974, if your truck was ordered with the 350ci and 4bbl carburetor, it was the 4 bolt main bearing engine block.

 

[AuroraGirl]

I hear a lot about how much fuel tanks for C10's are but I've never heard anyone say they had a tank the size I have in my '74 C10. I hear 16 gal., and 20 gal. but my tank is 18.5 gals. I know for a fact it is because I've filled it up from bone dry. What other trucks have tanks that big? Do 454 engines have tank sizes larger than 16? Does the engine size matter? I know that Blazers have really big tanks, but how are they plumbed? Do you think I got a Blazer tank in my truck but turned sideways? I know that sounds ridiculous but if the hoses would match up and they had it laying there, why not? Are there other trucks that have some tank size other than 16 and 20gal. sizes?

My truck seems to be made up of all kinds of parts not light duty C10, like the leaf springs are K10 leaf springs, from the factory. Unless that old man up in Mena, Ark. the one owner I bought it from, ordered it that way, but otherwise it's an ordinary C10. Like it has a half a Z28 engine in it from the factory (I later made a whole real Z28 engine out of it), you know that man didn't tell them, "Hey if you find half a Z28 engine laying around, pop it in there for me." when he possibly ordered it? So, I don't think he ordered anything. He went to the lot and bought it, like it was all morphed up.

I think its 16 gallons normally. you arent supposed to fill a gas tank literally all the way up, which is where you get 2.5 gallons my guess?

 

[75gmck25]

There were also vendors for dealer-installed dual saddle tanks. The telltale sign is usually a non-standard switch, often a simple metal SPST toggle switch instead of the black rocker switch on the dash.

The dealer-installed aux tank on my K25 was just a welded up box shape, and way different from the other tank. One convenience it had was a petcock in the bottom so you could drain out gas. Real convenient to get gas for the lawnmower or chain saw.

 

[idahovette]

@75gmck25 I had that same tank on my 75K20. installed it after I found out I could only go maybe 200 miles on the one tank(20 gallons). Big squarish box with all the parts to make it work like the dual tank option from Chevrolet. Toggle switch where ever you wanted to put it. Took it out a couple of years ago, sitting outside completely sealed up waiting for someone else??!!!

 

[Grit dog]

@Raider L , to my understanding 16 or 20 gal were the only saddle tank options.
You don’t have a blazer/burb tank. They’re in back between the frame rails.
I always “thought “ 16 gal = short bed truck 20 gal = long bed truck.
Your truck should have a 20 gal. Of which 18.5 when pretty empty is about right.
Like @AuroraGirl said, that is the nominal “full” capacity and there is still room for expansion. How much? Who knows or cares, but theoretically you can slowly fill your tank above “full” by some amount by filling the remaining expansion area.
But unless you literally pee’d the extra gas in very slowly, it’ll kick the pump off before filling the expansion area.
$20 says you have a 20 gallon tank unless it’s been changed out. And idk if the rear bracket is located the same on the 2 tank sizes.