440 owners - a question

[3C's & a D?]

Double pumper on a stock engine, that's never a good thing. I'm always surprised at how many people run them in their street cars and figure "that's just how old cars smell". No, that's how an old car that's running rich smells! As if old cars don't get bad enough mileage already. Kudos for noticing the problem, not accepting it, and finding the cause!

 

[RemCharger]

It has fresh, ethanol-free 93 in it. It has a brand new Holley 4160 in it, and I have adjusted the choke to open fully quickly (electric choke).

I assume it isn't a stock original rebuilt replacement.
They had a trick mixture screw hiding, that worked In conjunction with the 2 outer screws.

 

[413]

Dump that Holley and get an AVS2. Brighter days ahead.

or should I say that a rich or lean mode can be normal with an improper Holley 4bbl on a stock engine. LOL

 

[Todd Peterson]

I assume it isn't a stock original rebuilt replacement.
They had a trick mixture screw hiding, that worked In conjunction with the 2 outer screws.

Nope, not stock. I had rebuilt the original 4160 but it was too corroded to save. Got the new 4160 straight from Holley.

 

[weim55]

Try advancing the timing a couple degrees at a time. If it runs better or the same, advance it a couple more. If it runs worse (I bet it won't) retard it a couple degrees. The outer ring on the balancer can slip and give you false timing readings.

The "back pressure" is a myth. If anything, the car would be lean from a less restrictive exhaust.... But really, glass pack mufflers aren't any less restrictive, just louder.

What he said plus one more:

The likelihood of the outer balancer ring having moved on the hub over the years making the timing mark inaccurate is VERY common. Carefully set timing by ear until performance comes back and you can set proper idle calibration on the carburetor.

May have jumped 1 tooth on the timing chain/sprockets. The engine will still run with this condition but very poorly. It’s too involved for me to explain how to diagnose here, but you can easily source the information.

Steve weim55 Colorado

 

[Rick T]

I'm going to make this post more general than specific to my car, because I've ruled out the entire fuel system in mine... For those of you that have the 440 engine, do any of you find that, in spite of everything you try, your engine LOVES to run rich, to the point of occasional misfires?

I've already addressed the whole fuel system, including brand new carburetor. Everything is lean as it can go without running rough, but still runs rich.

I'm kinda looking at the possibility of ignition, since I have a 1967 440 that some fool in past converted over to a 1970 electronic ignition system, but - with timing within spec, can ignition really make it run rich?

The only other anomaly is that the same fool that did the ignition in past also put dual straight pipes on it with just glasspack mufflers. I am pondering if it could be the near complete lack of back pressure in the exhaust.

Again speaking in general, and not to my vehicle specifically, anyone have similar "always run rich" experience with their 440?

Update: I am redacting the back pressure comment. I'm actually trying to undo the work of the fool that tried to make my poor car a drag strip queen, including the air shocks and drop shackles in the back. Fortunately my car never made it to the drag strip. The car is way too pristine to abominate in such a way. In the case of my car, no back pressure = WAY too $%^& LOUD.

Good luck however, I have to comment the fool that worked on the car before you I think it’s pretty funny how you say that apparently somebody doesn’t they gave you a big nasty red X

 

[cudamark]

Float level, jet sizes, and fuel pump pressure would be where I would start if the ignition system checks out.