issue with 73 catalina

[bigcat73]

Hi. I am Lucas. I have a '73 catalina 2dr with 400 motor, 2gc carb, th375 trans. Car has 72,xxx on it. Car is pretty original but previous owner decided to spray the roof white. When buying the car I noticed the car had a new starter, fuel pump, fuel lines, looked like the ignition had been gone through (however still points), and he had told me the tank has been cleaned. I believed him because it fired up on the first crank. I bought it and took it home. Put on buick rallye's and fresh tires when I noticed the water pump started to leak. Replaced it and the radiator hoses and went on. Drove the car very regularly with very few issues when one day I drove it to school and simply didn't want to fire. Had to have it towed home. Tested the fuel pump and it was getting fuel to the carb. The plugs were sparking too. So I had the carb rebuilt. Now it runs but over half throttle or so it will stumble very bad when trying to return to idle. I rev it up a bit and will bump up to a higher idle that doesn't sound right. I tested for vacuum leaks around carb and found none. Any ideas?

[Ringo64]

Got any pics of the Catalina? 

[Frosty]

A couple of quick things come to mind. 

1. Check your fuel filter. Remove it, and try to blow through it. If it's clogged replace it.

If the fuel tank was cleaned, it is possible for some of the gunk that was there o travel all the way to the carburetor. 

2. You said you have points still. Check to see if they've gotten worn. If so, replace them.

3. Check your initial timing. Is it where it should be?

4. Check the vacuum advance on the distributor - does it work with vacuum properly? Check the vacuum line to the vacuum advance, is it getting enough vacuum?