440 6 pack issues

AshW said
Hi, new here from the UK.

I’ve had a good strong running 440 for the last few years. Engine was stock other than edelbrock torker intake and Holley 750cfm vac sec carb. Ran great, plenty of power, nice and responsive.

I was recently generously given a 6 pack carb setup, believed to be original, on an edelbrock aluminium intake.

I have stripped the carbs, ultrasonic cleaned them and rebuilt, new gaskets, vacuum lines, intake manifold gaskets etc. I cannot find any vacuum leaks.

At the same time I installed a new pertronix billet distributor and flame thrower 2 coil.

Issues I’m having are:

With the transfer slot set to a square, the car idles far too low, and the idle mix screws don’t appear to have all too much of an effect on anything, however are set to 1.5 turns out currently. I’ve set the timing at 18 degrees as this is where it appears to be seeing about the most vacuum at idle.

With the idle as low as it is, the transmission will not go into gear without the engine stalling. Transmission is a stock 727 with a transgo TF2 shift kit. Has always worked great.

If I bump the curb idle up at all, the ported vacuum starts and affects the vacuum advance which makes everything worse.

Float bowls have all been set just at the bottom of the sight plug hole.

Thankyou in advance to anyone who replies, I’ve been playing around with this on and off for a month or so now, to no avail!

I follow the "Four Seconds Flat" theory of running manifold vacuum to the distributor. If your peak vacuum is at 18 initial, what does your total timing advance to with all the advance in (32 to 36 degrees total mechanical advance?), and at what rpm does that occur?With the vacuum advance the total timing will be higher for better efficiency on the open road. The vacuum advance falls back to your total mechanical plus initial when you mash the gas pedal.

When you hook your vacuum advance to the manifold, at what RPM does it idle at? Can you adjust it to around 800-850RPM? Where are the throttle blades of the center carb in relation to the transfer slot at that setting?

I disconnect the linkage to the outboards completely and dial in the center carb first. The idle bypass bleed screws are covered with a lead plug from the factory unless they have been cleared of that obstruction. The outboards do pass fuel at idle and have adjustable bleed screws. Make sure the idle transfer slot on them is properly adjusted too.

Invest in a good Air Fuel Ratio gauge to help dial in the jetting at cruise and wide open. I like the DC Mechanical Carbs better personally.