So I ran out of gas. I think. Maybe.

[Mack B]

The truck in question is a 63 C10, with the stock tank behind the seat.

This truck and I are getting reacquainted after I ignored it for a few years. To get it back on the road I had to pump out the tank, replace some fuel line, the fuel pump, and rebuild the carburetor. During this I found a hole in the fuel float in the tank, so I repaired that. It's been road worthy for about a month now, I've put about 250 miles on it in that time.

Today I had the rare opportunity to use the truck for work purposes and I drove it round trip about 70 miles. At about 60 mph the engine turns about 3000rpm and it averages about 8 mpg...worth every penny.

About 10 miles from home on the return trip, the gauge reads just above 1/4 tank. Everything is fine, then I notice the truck is slowing down, I give it more gas, truck doesn't respond at all. It's like I didn't press the pedal any harder. I keep it hammer down for a few more miles and soon I'm only running about 35mph, I pull over and the truck immediately dies.

>it fires right back up
>fuel pressure gauge at carburetor is rocking more than normal
>it dies before I get back inside it
>re-fires fine, it struggles to drive away
>I pull in to a gas station, it dies a few times but cranks back up no issue

I fill it up, it holds 11 gallons. I immediately think this isn't the issue because I'm fairly certain I've put more than 15 gallons in it during a fill up before. Truck cranks up everything is back to normal.

My questions:
How much does your tank hold? I've done a search and see the replacements are 17 gallon, but members say anywhere from 13-21 for stock capacity.

I know it's possible, but is it probable the tank holds an unusable 5ish gallons?

Any other input into what may have happen here?

Anyone read this far and want some nude pictures of my neighbor?