Posted By: Paladin
440/Holley 750 Loading Up At Idle - 11/06/10 12:34 AM
I have a '78 Monaco former CHP unit with the original 440 Magnum which has been rebuilt. It has a small cam in it, unknown grind, Hooker Super Competition headers and an aftermarket dual exhaust system. Stock ignition with a recurve on the distributor.
Recently I have been working the bugs out of it (has not been driven much in a couple of years). Needed a carb for it so I pulled a Holley 750 VS off the shelf I had laying around, along with the intake from a '69 Chrysler 440. Carb was in very nice condition but I put a kit in it due to needle seats getting hard and gaskets drying out.
Works great when you first start it up, but after it warms up a bit at an idle she starts slowly loading up. It is running rich; you can smell it and see the cloud of smoke start forming in the garage.
Like I said before, carb was in good shape internally and had the stock "72" jets in it. This is usually pretty close jetting for any other 440 I have worked on, and that has been over a lot of years. It has a brand new power valve in it. Wet float setting is dead on. I used a Holley rebuild kit. Idle mixture screws don't make much difference when you adjust on them. When you pull the PCV hose, she idles way-y-y up. Altitude is about 2400 feet.
My inclination is to pull the bowls and drop down to about a "68" jet. But before I do, I thought I would see if anybody else has been to this rodeo before, or if I might have missed something.
Ideas? And thanks.
May God bless America,
Paladin
Recently I have been working the bugs out of it (has not been driven much in a couple of years). Needed a carb for it so I pulled a Holley 750 VS off the shelf I had laying around, along with the intake from a '69 Chrysler 440. Carb was in very nice condition but I put a kit in it due to needle seats getting hard and gaskets drying out.
Works great when you first start it up, but after it warms up a bit at an idle she starts slowly loading up. It is running rich; you can smell it and see the cloud of smoke start forming in the garage.
Like I said before, carb was in good shape internally and had the stock "72" jets in it. This is usually pretty close jetting for any other 440 I have worked on, and that has been over a lot of years. It has a brand new power valve in it. Wet float setting is dead on. I used a Holley rebuild kit. Idle mixture screws don't make much difference when you adjust on them. When you pull the PCV hose, she idles way-y-y up. Altitude is about 2400 feet.
My inclination is to pull the bowls and drop down to about a "68" jet. But before I do, I thought I would see if anybody else has been to this rodeo before, or if I might have missed something.
Ideas? And thanks.
May God bless America,
Paladin
Then with the vacume reading you can determine if you have the correct power valve 
