Stock open chamber 440 heads will run best at 38 degrees total advance at 3000 rpm plus whatever vacuum advance. This is the collated result of 10+ years of reading dyno articles, posts, etc.
You really need a high performance curve in your distributor. That will allow more initial advance whle limiting high speed advance to the above-mentioned 38 degrees.

An Edelbrock Performer RPM should be on your buy list, it's worlds better than a factory intake, if you can fit it under your hood. Drop base air cleaners were made for this problem.

The 750 Edelbrock has a very checkered past. There's a reason that most of them sell used on the 'bay for $75 or less. But, if you have not rejetted your carb you have a huge problem. Manual choke Edelbrocks are set up rich for sea level at the factory, because the feeling is they will be used for drag racing. At 5800 feet your carb is probably at least 4 stages too rich. Living in Lakewood, CO I had a 600 Holley on my ride and I'm down from 65 or 66 jets to 60s on the front. So you need to go to the Edelbrock Web page and figure out what you need for four steps leaner. That should get you started in the right direction. If you're going to throw that carb away throw it in my direction, I need a body. But you can probably tune it to work a heck of a lot better than new.

My Golden friend's son traded a 600 Holley that had been tuned for a 625 Edelbrock manual choke carb and immediately lost 5 mpg. My friend worked and worked on the jetting until the car ran good and mileage was back up, and I think he may have gone even more than 4 stages leaner.

R.