i have a 350 11:1 comp., .555 lift roller cam, edelbrock intake, holley 4150 carb. i cant get this thing to idle. ive been through the idle circuit several times now. it only runs when i stay on the pedal. vacuum leak is not the cause. probably should mention 11" stall converter. anyone help?

What is your vac at 800 rpm?

i cant go that low due to cam. i idle at 1500 rpm without load. in gear it dies, im thinking looser converter will cure it.

I'm not a pro at this but at 1500rpm I think you're beyond the idle ckt. What are the rest of your cam specs? Also what's the advertised stall on that converter?

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...Dennis
'69 RS Convertible w/SS trim (http://www.camaroslimited.com/memberscars/den.htm)
'96 Z28SS #1679 of 2410 (http://www.camaroslimited.com/graphics/memcars/96ss.jpg)
"The Club" (http://camaroslimited.com)

.555 lift int&exh 330 degrees advertised duration @ 050. 1.5 ratio rockers. stall speed is 2500rpm.

You said "330 degrees advertised duration @ 050". Do you actually mean 330 degrees advertised and about 280 degrees at .050 ?? Either way that is a really big cam, 1500 may be normal. The power bandwidth would be 5000 rpm to 9000 rpm!

yes it is 330 degrees advertised. and 1500 is a fine idle speed, but i cant keep it idling in gear unless im on the pedal. the second i drop it into gear it dies.

Man that is a HUGE cam! Do you have like 4.56 gears and a 4000 stall? If you plan on driving that on the street, it's gonna kill you.

What are your plans for the car?

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383 Speed-O-Motive stroker kit with Speed Demon 750, RPM intake,Proform HEI dist.MSD6a box,World Products Sportsman II heads, ported and polished with 2.02/1.60 valves,64cc,TRW forged pistons with 10.7:1 compression, Comp Xtreme 284 cam,Crane pushrods, Comp Cam 1.6 full roller rockers,ATI damper, 40 series Flowmasters, 4.11 gears with TH350 and 3000 stall.Powertrax NoSlip Locker

Man, with that size cam there is no idle. Ever hear a Pro Stock car idle, maybe 2000 rpm, but they don't have to. Case of too much bumpstick, must really suck the petrol, huh?

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69 rallye green X77 Z/28,1967 SS 396 Conv. 1974 c-10 454 swb

I'm going to say that you probably don't have anywhere near 280 duration @ .050 with only .555 lift; when you get up in the 280 @ .050 range most any cam manufacturer has at least .660-.700 lift.

If you're positive there are no vacuum leaks, it should idle below 1500 rpm in park. It does sound like you have way too much primary throttle blade opening. With the car off, turn the throttle idle speed screw clock-wise closing it down and count the total turns until the throttle blades are closed. If it's more than 1 1/4- 1 1/2 turns it's probably too far. Remove the carb and turn it over and adjust the secondary throttle blade screw to open the secondary blades slightly. This would be a good time to remove the screw and re-install it from the top side so you don't have to remove the carb for any further adjustments. What you're trying to do is get more airflow at idle so you can bring the primary idle adjustment down (butterflies more closed). There is a transfer slot on the primary and secondary side which you can see from underneath the carb; you can just see the bottom of the slot from under the throttle blades. You want to keep only .020-.030" of the slot showing when the throttle is closed.

If adjusting the secondaries still doesn't get the primary side down then you may have to drill small 1/16" holes in the primary butterflies (one in each at the front of the blade). BEFORE you do this I'd call the Holley tech guys; once you drill them you can't un-do it. But often with a large cam you need to get the extra air so you can close the idle blades down and get the adjustment back for the carb idle mixture screws.

I've had some very large rollers before but I never needed a 1500 rpm idle. I think you need more airflow through the blades and get the primary blade closed down so you can get the proper mixture adjustment and idle speed.

Jody

I would personal take another carb that is known to idle on something else and install to see if it will idle then if so i would invest in another carb i have run across similar problems with holleys that wont run or idle circuit gets dirty after sitting and carb starts doing wierd things anyhow thats my 2 cents worth

Camcojb has it exactly right what happens is the throttle blades are open so far that it is idling in the main circut and not the idle circuit it just wont work that way

camcojb you are the man. thanks.

Did it help you? Cool!!!!!!

Jody