[Nantooch]

Dennis, Paul

Was trying to readjust my idle using the vacuum gauge. If I try to get to #14 I've got to adjust the idle way up there..(dont know actuall as I dont have a tac) I've tried to adjust according to what Dennis had said in an earlier post dealing with Holleys. Got the mixture screws set at 3/4 turn as just below that it begins to stumble. From earing it. I'd say that to get to #12 vacuum it has to be idling at around 1100 or so. I went back through and retorqued all the manifold bolts, but havent sprayed any carb cleaner around the manifold as of yet. I do know that at present that if I set the idle so that I'm at #12 I get the nasty case of run-on afterwards.. Any other clues I should be looking at to correct this?

[67RS502]

Sounds like you have it idling too high if it wants to keep running.
Any particular reason you want 12" of vacuum??
I wouldnt worry too much about vacuum, just set the fuel mixture screws
so you get the highest idle rpm, then stick it in gear and make sure it
idles well in gear, if it wants to die or has a "weak" idle fatten it up a bit.
Also 3/4 of a turn sounds too lean if it wants to stumble, try 1 to 1 1/2
turns out and adjust from there to get the highest idle rpm, and if its a
4-corner idle carb make sure to go over all the screws twice.

[Nantooch]

67RS502,

Thanks, was just trying to get the vacuum up to make sure the PB had enough. From the reading that I've done, seems that #12-14 was ideal for the system. If I leave it where it is now, it idles around #5-7.

[DjD]

I think you missed something in my post... You don't adjust the idle screw for most vacuum. You set the idle and adjust the mixture screws for most vacuum. The 3/4 turn out on the mixture screws is where I've found most Holleys end up being when well tuned.

[Nantooch]

Dennis, think I got it straight. It stumbled at about a half turn, so reset it to 3/4 turn and adjusted the idle down. Ran it through WOT with the dist unplugged and the vacuum plugged. No pinging or knocking. Reconnected the dist and adjusted the idle back down. No run-on at shut off running at 8*.

thanks again for the info on the other post.

[rojo]

Brandon, For what it's worth mine idles with between 10 and 11.

[Nantooch]

I'd like mine there, but engine run on and a faster idle I dont want. I had tried it all set before with the mixture screws out at 1.5 turns, but got black fluffy plugs from it. Will have to see what the 3/4 turn does to em now.

[pdq67]

I'm sorry guy's but you all probably know more about carb's then I do b/c I always just ran a stock Q-Jet that I reset the floats and idle jets on and never had much of any problems at all.

The 750 cfm, 3310-2 I am going to run on my 496 is the first Holley I have ever messed with so I am still learning about it..

pdq67

[travis]

With a 270 magnum even a 327 should pull at least 12" at 800-900 rpms. Have you re-adjusted the valves to make sure they are not set too tightly? Are you running manifold or ported vac for your vac advance? Is your 10.5-1 compression actually measured, or a "ballpark" guess?

[Nantooch]

I've rechecked the valves once since the build. Probably could stand to recheck em again.
Running manifold vac to the distributor, ported to the tranny,
Pistons are 10.5:1 with 64cc heads. Subtract a fraction for the .042 gasket. So may have dropped a hair, but still within the 10.3 - 10.5 range.

Well to update it..Rechecked valves this morning using the EO/IC method. MADE A WORLD OF DIFFERENCE!! Vacuum up to #12, idles easier, hell of a lot more responsive, and seems someone stuck a couple more ponies in there some where. Thanks for the help on that Travis. Muchos Gracias. [img]graemlins/thumbsup.gif[/img] [img]graemlins/thumbsup.gif[/img] [img]graemlins/thumbsup.gif[/img]

[ 09-02-2004, 11:05 AM: Message edited by: Nantooch ]

[travis]

Your muchos welcome [img]graemlins/thumbsup.gif[/img]