holley problem

[Shields14]

i have a very new holley 670 street avenger and have had it on 2 different 440s and i have had the same problem with both and that is i can screw the idle mixture screws all the way in and thats where it runs best, if i screw them out at all it starts getting worse , i have changed to a lower power valve 4.5 , pulls about 7 on vaccume guage , any thoughts on how to fix this thing i really would like to get it idling better than it is im running the car on the 4th so any help would be greatly appreciated.

[c00nhunterjoe]

Screw all screws in then back out 1.5 turns. Start adjustments from there for idle mixture. A 670 on a 440 is small imo. Will probably need a jet kit and accelerator pump cam kit to start.

[69wannabe]

A 3310 holley 750 or a 4779 750 double pumper would be a better carb for a 440. You really will see a difference when you take that 670 off and put the right one on there!!!! I put one of the 670's on my 440 a few years back just to get it to a show since my 750 DP was off with a leak and it pretty much killed the car. It was like night and day difference and I got my 750 back on there the next day and it was back in business!! just my 

[c00nhunterjoe]

The 4779 is hard to beat. I run it on my 383 and love it.

[Cooter]

i have a very new holley 670 street avenger and have had it on 2 different 440s and i have had the same problem with both and that is i can screw the idle mixture screws all the way in and thats where it runs best, if i screw them out at all it starts getting worse , i have changed to a lower power valve 4.5 , pulls about 7 on vaccume guage , any thoughts on how to fix this thing i really would like to get it idling better than it is im running the car on the 4th so any help would be greatly appreciated.

If the idle screws are all the way IN, that indicates an overly rich condition at idle. Yes, the 670 CFM carb 'Might' be a little small at like 7000 RPM for a Wild 440, but all but perfect for a mild/stock 440 with little camshaft/manifolds. I run a modified 650 DP Holley on my own mild 440 and it loves it. Throttle response is all but Fuel injection great. I'd be looking into something like Floats too high causing over rich condition at idle.

You should be able to at least adjust the mixture screws and see a difference. If your having to lean it out, then something's running far rich.

[Chryco Psycho]

i you ar eonly making 7" of vacuum how high is the idle speed , the idle transfer slots maybe uncovered losing sensitivity to the screws , you may need to drill a hole in the throttle plate to allow more air in without opening the throttle up , star with a smaller hole around 3/32 on the opposite side of the plate away from the idle slots .
Personally even on a mild 440 which yours is not the 670 is too small , the factory used 750s

[Shields14]

alright i have a 750 dpumper i will stick on it and try.  im gunna try dropping a couple jet sizes and try that on that street avenger first off and just see if it will clear it up at all. float levels all good . i ripped one of my gaskets so i got new ones ordered i will keep you guys posted but i am thinking like you guys might be a  bit on the small side even once i do get it straightened around.

[Shields14]

also i am at about 4700 feet above sea level. and if i screw the screws all the way in it starts running better but wants it leaned out more so gunna try new gaskets and smaller jetsd if that dont work dpumper is going on. gotta run it next week its on a chrysler  new yorker 77 so was trying to stay with the vaccume secondaries but if i need i can put the double pumper on it..

[Shields14]

i dont know what to do with this thing i have replaced gaskets power valves, tried didfferent jets up and down, it has been on 2 different motors and 3 different intakes i really think something is wrong with the carb from factory.i cant lean it out enough on the idle circuit.

[Shields14]

the idle is around 600

[Shields14]

secondary slot was completely covered adjusted it and the primary and all is golden now.  thanks for all the help from you guys was about to chuck the dang thing in the garbage.i have had a crash course in holley carbs the last few weeks but with your guys help i got it figured out.keep up the good work some of us out here only have sites like this to figure this kinda thing out even as simple a problem that it was.