How much does temperature affect motor?

@Mattax Thanks for the reply. You left a lot of good info and I'll do my best to answer as much as I can. First off, you mentioned that the exhaust might have the extra ports under the headers, I know exactly which ports you are talking about because the 360 that came in my dart had those (plugged by the time I got the engine) and the one I put in did NOT have those.
The tank in my dart had rank fuel when I got it but was completely rust free and clean inside. it was emptied and has clean gas in it now that I put in about 1 month ago. I don't let the gas get older than 2-3 months tops before I burn through it all.
As stupid as it sounds, this carb holds sentimental value to me because it belonged to my father and he daily drove his car for so many years with no issues with it so while I did change out the cap to the vacuum secondaries to make tuning easier, I kept all the original parts and I would never do any irreversible changes to it even though I have no intention of selling it.
When I got the carb I did buy a trick kit and an assorted box of holley jet sizes. I replaced both primary and secondary power valves with the equivalent sizes to what was there when I opened it, and I replaced the jets with new ones to equivalent size (jets were 76 primary and 82 secondary) along with new gaskets on the fuel bowls and metering plates and then I set the fuel level while at idle (just barely weeping out of the sight hole and the engine was idling at about 850-900 rpm where its very stable) My mechanical fuel pump delivers fuel at about 5-5.5 psi at any given time according to the fuel pressure gauge mounted on fuel rail by the carb.
I drove around and I noticed that I was basically dumping raw fuel at all times so I played with my jetting gradually bringing it down to 70 primary jets and 76 secondary and then bringing it back up to 73 and 79 because that is where I noticed the *least* amount of stumble and the engine seemed happiest (and exhaust stopped stinking of fuel). My engine always had an issue of shaking around quite a bit at idle like something was off so then I played with the timing and idle speed and idle mixture screws until I got up to that 15ish* point of initial timing where the engine has seemed the happiest but something still just seems really off to me which is why I made this thread. I realize that I might have been tuning in the wrong direction and I have gotten a TON of help so far as I hope to apply it all soon to keep my dart happy and driving for many more miles.
As far as the loudness of the engine, I believe that a big factor is I suspect the headers aren't sealing too well at the flange with the rest of the exhaust system. I have new high quality header gaskets that I bought at a local performance shop so I know there aren't any leaks there. The noise is completely bearable but would easily drown out a lot of 'engine noises' such as fuel boiling in the carb. That will be a problem for another day, for now I will look at the carb and nothing else.