With my new cam my 440 idles beyond rough..looks like the motor wants to jump out of the car..It shows 12 inches of vacume..I had a 5.5 power valve in I had a new 4.5 valve so I tried it.didnt seem to help.The motor comes alive as soon as I touch the gas ,but idle is nuts..need input.. Thanks

PV should be 2" less than the idle vacuum in gear if it's an automatic and i believe it's half the idle vacuum if it's a stick car. Adjust your idle mix to get the best vacuum the open another 1/4 turn.

12" Hg is a pretty mild cam. Need more info. Degreed in?

cam is hyd roller..degreed in at 107, gross lift is 530 intake and 530 ex, duration @.006 284 in & 292 ex, seperation 112 ,duration @ 050 intake 232 ex 240..Idles bab bad ..off idle comes to life....I'll check vacume again tomorrow

The power valve has no effect at idle.

It sounds like the idle or possibly the transfer circuit is lean, based on your description. Can you tell from the smell whether it's excessively rich or lean at idle? Any clouds of black smoke?

Look here

http://members.tccoa.com/392bird/carbtech.htm

& scroll about halfway down to the photo of the carb ,main body and metering block.

In the metering block, be sure 25 is not blocked. Spray some carb cleaner through it until you know it's clear. Ditto 6 and 4. Remove the idle mixture screws first.

Continuing with the aerosol carb cleaner in the main body, be sure 3 is open to the idle discharge port (below the throttle plates when they're closed) and 4 is open to the transfer slots (above the throttle plates when closed). Be sure 6 is open to the idle air bleeds (a brass orfice, one in each barrel).

Has the carb ever been rebuilt? The wrong main body to throttle plate gasket can block off a passage necessary for idle/transfer.

Is you PCV stuck open? That would cause a huge vacuum leak, the effect would be worse at idle.

If we knew if the idle was rich or lean, it would help.

Jim

What RPM are you trying to idle at???????

too mild of a cam.

need at least 360-361* duration. and a 1" lift at the valve.

You want the all valves open, all the time. It will scream like a jet.

Initial timing is 15 ...total is 34.If I idle at 1100 it's livable but still bad..Its auto trans..I'm sure its the air bleeds as it has the pro form center section..when it had the crane hys roller I couldnt get it to idle,so I set the whole carb to pro form and they set it up it idled fine.. ..NO Charge ..they were good to work with,,,but now after the regrind....bad bad

will a vacuum advance workn on it? or is the idle too poor to pull vacuum right for cruising.

If you can't get it to settle own for tunning, you may need to, "spring load" the carb's needles and seats. holley has a kit. dail it in to baseline, and you might not need it. but doesnt hurt.

Get an overflow bar , if its really shakin.

Then set the timming. Use a vacuum advance distributor with a extra 12* pulling idle vacuum @ manifold.

SOMETIMES... you can get lost in the forest/trees thing...
In the last 10 years or so I had 2 motors that just plain wouldn't idle, I am not stupid, but after chasing these things for too long, I figured out what many of you already know.Some combinations NEED a short and quick advance curve(they need more than "stock" initial advance, but no more that 35-38 total at about 3K.
If you set the initial where it will idle OK, it has waaaay too much total, and the opposite is true
i.e. I was using stock type distributors as triggers.The first one(1 452 RB with the old .509 MP purple)just got an old cast iron tach drive DC electronic distrib.
The second was more recent, and I ended up welding up the advance curve slots below the stator plate about 1/8" and it runs like never before.Not saying this is your problem, but I wasted a lot of time and endured dirty looks from my wife as her car wanted to conk out/overheat/or take off at 1500 rpm idle depending on where I tried the timing that day
Luck, Casey