How much timing do you have at idle? You should be at 20 btdc or more with that cam.
Use your vacuum gauge and adjust timing to highest vacuum then back off between 1 and 2 hg adjusting idle to 900 as you go, if it starts fine when hot your good to go.
By giving it more advance the idle will increase, then bring the idle back to 900.
By closing the throttle plates more it will bring you back into the idle circuit so you can properly adjust the idle mixture screws.
If you are in the idle circuit and you bottom out the mixture screws it should die or come close to dying.
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I just put a 6 pack on my 440. It seems to surge when under a load at around 65 mph. Not sure what to do. I have metering blocks in the out board carbs with 79 jets. Any help would be nice.
That's a lean surge, center carb should have #64 to 66 jets, if your vacuum is less than 12 at idle use a 4.5 power valve otherwise 6.5 is ok.
outboards should have 82 to 86 jets with long yellow springs in the diaphragms.
Stock will be in the lower sizes, big cam in the higher sizes, all engines are different
This info was given to me by Bob Karakashian (AKA Mr. Six Pack), he lives a few miles from me and is a genius when it comes to six packs, google his name.