Trying to get my 350 to run better

[Orion88]

My 79 Silverado is a good strong running truck, but there are some issues that are annoying me that I'd like to fix if possible. I'm not the most experienced gear head so I don't know all the little tricks and secrets to getting your engine to run as optimally as possible all the time.

A little about the truck: 79, 2wd, SWB, 350 sbc, th400, 3.55 posi. The truck has 12,000 original miles. It was a show truck most of its life. Now its my daily driver in the warmer months. The engine has a brand new Edelbrock 1405 carburetor sitting on a Performer EPS intake, and it has hei ignition and headers, other than that everything on the engine is stock. Initial timing is currently set at 8 degrees, thinking about bumping it up to 12 degrees. I just replaced the spark plugs for a new set of AC Delco r45ts gapped to .045.

The issues: It never fires right up and goes in the morning. Usually it takes several tries and pedal pumps before she will idle on her own. Then it needs to warm up for a minute before I can go without the risk of stalling it out. A manual choke would probably help this particular issue. Any other suggestions?
Also, when I go to get on it from a dead stop or at low speeds it stumbles. I understand that a stock truck 350 isn't going to plant me in the back of my seat, but it should squeal the tires a bit in my opinion. So what's the issue? Too much or not enough fuel? Or something else?
Lastly, it idles rough. I just changed the spark plugs hoping this would fix the issue but so far it hasn't. The old plugs looked like the engine had been running rich, but I also just changed carburetors, and the previous carburetor was not running right at all.

So... what's causing these problems and how do I go about fixing them? None of them are bad, just annoying. And most importantly, I want my truck to perform as it should. It bugs me that something's not right. Are there any simple fixes, like Seafoam, adjust the accelerator pump (currently in the middle position), more timing, etc that I can do? Things I should check? Any and all help would be appreciated. Thanks.