We really haven't discussed your ignition system . Your plugs and wires need to be working 100% in order to tune the rest of the engine. A good strong coil and timing set to where your engine likes it is crucial to getting the mixture to burn at the right moment. That's why I like multi-spark CD type ignitions because they clean up the idle with a more complete burn.
Gus

I really hate to say this but at the risk of sounding like a WA, do you know anyone in your circle of friends that is a motorhead? Someone who knows the ropes can often spot something in ten minutes it would take you hours to find. I know experience is a good teacher but I'd hate to see you harm your engine with extended running on what seems to be an extremely rich mixture.

If you dont have a timing light set your idle mix screws to max vacuum, adjust idle, then do the same with your timing at idle. Redo idle mix screws. What is your vacuum now.

[quote] Ran so good before I took it to a shop here for supposedly “replacement of the pick up coil in the distributor”!!! [quote] Bill what was the issue then?

A genuine Holley style needle and seat does not use a locknut. It has a thin unthreaded nut that screws the seat in and out and then a wide sloted screw that locks it. If yours have thick brass locknut's then your guy put an el cheapo rebuild kit in your carb. That style nut is easy to overtighten and strip the threads in the fuel bowl. The cheap kits also come with cheap gaskets that shrink and/or stick and the powervalves are garbage. If yours has the big brass locknut's then you need to buy a good kit from Holley or Quickfuel and then find someone else to do your carb. I've attached a pic of the correct adjuster to compare with yours.

Next you need to understand how the idle speed screws affect the transfer slots. If the throttle plates expose too much of the slot then the amount of fuel that will flow at idle is affected. If the plates are over open enough at idle then enough air will flow through the Venturi boosters to start flowing unwanted fuel from the main circuit. There are many posts on here that explain these issues well.

Ignition timing is critical. It bears repeating, Ignition timing is critical. If you are setting it to some smog spec it will not run properly. Your distributor may/will need to be modified so that you can have enough initial timing without having too much total timing.

Powervalves are often misunderstood. Pv's add power enrichment, never idle enrichment. Even some of Holley's literature is incorrect. Powervalves add fuel to the main jet circuit. No fuel feeds through the pv until there is enough airflow through the venturies to start fuel flow through the main jets AND the vacuum is low enough to open the pv. No matter what vacuum number is on the side of the valve it does not add fuel to the idle circuit no matter how low the idle vacuum gets. You could put in a pv that opens at twice your idle vacuum(not recommending that) and it will always be open but it still will NOT flow extra fuel at idle.
If you can screw the idle mi xture screws all the way in without stalling the engine then the powervalve diaphragm is likely blown and dumping fuel directly into the vacuum passage from the manifold.

Had the same exact problem,, I replaced the carb.. installed a Elderblock,, runs perfect.. Mine also is a 78 440

So I finally had some time to work on this. I checked the fuel pressure, when I first started it, pressure was at 5-6 psi at idle. When brought the rpm up the pressure went up to past 10 psi, maybe around 12 but 10 is as high as the gauge goes. When I let off the gas the pressure went down to 4-5 psi. If the pump is working properly, should the psi be at 6-7 all the time, at idle and highway cruising???

It started and ran fine but after I drove for a few minutes and turned it off, it wouldn’t start again, cranked good but just wouldn’t start. The next day all was good, started right up but again after driving a bit and turning it off, same thing, cranked good but wouldn’t start. So took it to a shop here and that’s when I was told that the pick up coil in the distributor was bad. Got it back from them and no more of that issue, but since, when I got up to 55-60 it would start cutting out and nothing but issues now.

Yes I can screw the idle mixture screws all the way in and makes no difference to the motor, sounds the same.

I was thinking to switch out the carb to an Edelbrock, which one did you put on yours, does it have an electric choke?

Yes I have what is in your pic. I’m just baffled as to what this shop did to cause whatever problem I’m having when it was supposed to be a simple repair. Maybe I should take off this Edelbrock intake and put the original intake back on. I did talk to an Edelbrock rep last week and he said it’s highly unlikely that their manifold is causing my issues.

Unfortunately I don’t know anyone up here and now I don’t trust any of the few shops that are up here. I totally get that having a motorhead look at this thing would be the best thing. I’m going to have to keep asking around.

I’ve adjusted the idle mixture screws a few times, makes no difference to the motor, can still screw them in all the way with no change to the motor. The vacuum is at 15-16, needle bouncing back and forth. The shop suggested that I have a vacuum leak and referred to the brake booster. I tested the booster according to a couple of YouTube vids and the booster seems like it’s ok per the tests.

THIS IS YOUR PROBLEM. It sounds like whatever fuel pressure regulator you have is not working. Fuel pressure should never get above 6 PSI regardless of the engine rpm. If it's a mechanical pump I would replace that. If you have a carter electric pump it has no separate regulator so it would need to be replaced. Most Holley electric pumps have a separate inline regulator that can be rebuilt.

I don’t have a fuel regulator on it, has a mechanical fuel pump. So I’ll replace it and see what happens after that.
Thanks for your help.

Exactly your problem, get a pressure regulator on that engine NOW!. You don't want your fuel pressure to exceed 6.5 pounds no matter what your RPMs are. Don't mess with anything else until you get the pressure corrected.

You might also want to make sure there's no gas in the oil. Diluted oil is hard on bearings. The oil may not read noticeably higher on the dipstick, so give it a sniff. You shouldn't smell gas.