Measure the coil outer diameters and you can calculate the spring rates.

From that you can figure tension at any given distance.

A few weeks ago I recurved the distributor back to the stock springs and set mechanical adv to 24 degrees total. Based on this I set initial to 14 degrees. I also have vacuum can hooked to full port vacuum (below butterflies). Reset the idle down to 700-750 idle mixture on the Holley using vacuum gauge and took the car for a spin. Felt much better off of idle whereas before with the single, light spring I could feel the mechanical advance making the car act very strange right off of idle releasing clutch to get the car moving. Bring RPMs up to not stall car, release clutch, drop RPMs slightly, etc. and it was causing timing fluctuation which I could feel in how the power was being applied. That issue is now gone!

Up through 2500-3000 RPM the car felt better, but putting it under load, up hill, and giving it some throttle cause a loss of power and cough up through the carb. Felt like a lean condition to me, so yesterday I had some time to play with the car some, and jetted up from the stock 70s to 73s. I left the secondaries alone (80s). Took the car for a drive and it now has a clean/strong transition under load and the cough is gone.

I've checked the float level a few times, and understand that the general recommendation is that fuel should dripple very slightly out of the bottom of sight plug with a rock of the car. This isn't very scientific... I need to rock the Dart fairly hard to get fuel to slosh out. I can see the top of the fuel level inside bowls (front and back are set the same) when letting sit/idle.

I'm thinking the float level might be a hair low, but what is the general concensus here? I was thinking of possibly raising it some and going from a 73 back to 72 on primary jets.

Progress!

Thanks!

I would go ahead & raise it to there.

Should I be looking for fuel to dribble out just when simply removing the sight plug, or only with a *slight* rock of the car?

It should start to dribble out running at idle with the plug removed. That being said, it should barely be weeping out, not pouring out in any way. If you rock the car then it should pour out a bit then stop when settling. Also, your primary jetting seems very light compared to where I've had my 383's in the past with the Holley 750, but those motors were not stock with stock cams. I wouldn't worry about what the number is, I'd just jet it where it wants to be.

Yeah, the 73s really helped, so it was lean. Its stock cam with RPM intake, headers, and the 750. Its running better and better the more I tweak it.

Okay, thanks. From what I have read from various tuning guides is that the lower threads just barely get wet / very light dribble of fuel. My floats are low. I'll adjust them up and keep tinkering.

I agree with the above. Somewhere around just dribbling out. Fine tune from there.


I'm sure that's what you meant. So its around 36 total on the engine.
When you get a chance, find out what rpm this happens.
And what is the timing advances to at 2500 and 3000.

Likely a source of the problem here.
Should be on ported. Only need or want around 12-16* at idle with a stockish engine. It's probably got 20* something and therefore runs nicer at with a lean mixture. But that lean mix is not providing power. With an automatic it would be more obvious, but its still true. Put it on ported, a little rich mix and it will burn faster and be good.


Good.


Good plan.
The other thing you can experiment with is richening the idle circuit.
One change at time, so try this afterword.
Easy way will be to stick a wire in each idle air bleed. (primary side only) Some magazine writers say this will only effect transition. In my experience that's horsepucky. It will help most in the transition, but it will effect the entire idle. You may have to readjust the mix screws.

You can use one wire or two. In either case, stick it in the airbleed, then bend it over the choke tower and run it under the air cleaner gasket. That way they can't move.
The idle airbleeds will probably be between .073 and .076" diameter. Measure with the shank of a small drill.
Calculate the area. then come up with a wire or pair of wires to reduce bleed about .003" diameter.
In otherwords, if the bleeds are .076" diameter, restrict them to the equivalent of .073 or .074"
I wouldn't take them lower than .070 unless the idle feed restrictions are real small, and I doubt they are.