[Blues Power]

Sounds like separate issues.

Check that your choke is fully opening.
Check that your accelerater pump Is squirting.

Check that your thermostat is opened by feeling the upper rad hose.
Make sure you actually have a stat installed

 

[Grimbrand]

"lean" doesn't really have a sound unless it's pinging. But that being said, your symptoms could be a problem with the accelerator pump! If it's been a hot minute since you rebuilt your carb, you might want to take it off and throw a kit in it. Most of them aren't too hard to do - but definitely look up the process and maybe watch a video. All of 'em have sneaky little easy-to-lose parts, like the check balls and rods in an Autolite. If you're not prepared, they fall out and vanish forever. If you know beforehand, it's no big deal. Many of the little easily-lost bits are in the kits anyway.

I am inclined to think this is not a "no gas is getting to the carb" issue; when that happens, it usually works fine until the bowls empty, then it stumbles and sometimes dies. That most often happens under WOT runs - and it goes great, until the car falls on its face. Your description just doesn't sound like a delivery issue to me - though it's still possible.

But don't be afraid to take a look at your ignition system either - if your spark is weak, it would do the same things! Maybe check the cap and rotor, to make sure they're not all worn out or burned up.

Best wishes Wyatt!