1967 Carburetor drains overnight

[ChiliPepperGarage]

All the gas drains out of the carb if the car sits overnight. I am assuming it is draining into the intake. I have to pour gas into the carb to get it to start. Once it starts it runs great.

I guess I have to do a carb rebuild?

 

[74 Harley]

There's several things to check, is the carb really dry or the choke not fully closing?
The fuel pump may have a sticky/ faulty check valve (it's been sitting awhile)
Have you checked for vacuum leaks? Even a small one can cause hard starting.
Does the accelerator pump work?
I don't think fuel can "leak" from the bowl to the manifold without being cracked.

 

[Pink T-Bird]

All the gas drains out of the carb if the car sits overnight. I am assuming it is draining into the intake. I have to pour gas into the carb to get it to start.

I'm going to work with the presumption that if you are planning to rebuild the carb yourself you have enough experience to have already confirmed the choke is operating properly.
It would be pretty odd for the gas to drain into the intake overnight, and if it did it is unlikely you would need to pour gas in to make it start the next morning as it would have more than enough already pooled down in there.
It would not be unheard of with 10% ethanol in gas for a portion to boil out and overflow into the intake in the 10 minutes or so after you park the car, but there would still be enough gas in the bowl to start in the next 3-4 days. Modern gasahol WILL evaporate from the carb if the car sets for over 7-10 days. That is why many folks go out of their way to get non-ethanol fuel in their classic cars.
You don't say what carburetor you are running. Is it an Autolite 4100? Holley 4150, 4160, or something else? That might lead to some specific research for a similar issue.
Off hand though, I agree with 74 Harley it is likely a bad accelerator pump or check valve for the accelerator pump. What you are doing by pouring in gas is mimicking the function of the accelerator pump that happens when you pump the pedal before starting the car. But if that were it, you would notice a hesitation when accelerating from a cruising speed too.
On a 4100 that pump diaphragm can be replaced while on the car but on a Holley it cannot. Either way be sure to order the Viton diaphragm so it will hold up to gasahol.
And as a final note, I recommend starting fluid rather than gas if you need to prime the carb to start it.

 

[OldGuy]

I have a similar problem with a '76. It will start the next day, but not 3 days later. It runs smooth, so i doubt it's the accelerator pump. It sounds as if it might be the fuel pump. How can I check for drainage? The only thing I know to check is the pressure.