ok heres the deal my 71 chevelle with a 307 was having a very hard time cranking up when hot or sometimes cold changing the timing had not affect at all.so I changed plugs and wires no change. so I finally changed the distributor and while at it I switched to a 4bbl holley carb and peformer rpm intake me being dumb(im only 18) reused the old gaskets big mistake cranked it up it had a very high idle and white smoke every where.Replaced the gaskets with new ones no more smoke but a high idle like 1500 rpm or so and cant really get it to go down any suggestions? any one know how to tune this holley I belive it is a 4150? please help Im bout to go get a honda if things dont get right or somebody might just find the chevelle in a river

Give more details about what you've tried to get the idle down. Which screws have you turned? What is your ignition timing? Does the carburetor have a choke? If so, have you adjusted it?

It's hard to give tech help online without more detailed information.

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My Web Page (http://www.landry-family.com) (updated 06-21-02)

"Long Live Freedom!"

Chad Landry
TC Member #643
ACES Member #4556
'68 El Camino

Did you change the accelerator cable? It's about 1.5" too short for the 4bbl conversion. Depending on your transmission you will also have to modify the cable/rod assembly. You might also want to check the spring tension for the return.
Fred

ok I got the car to crank up but it runs for about 10sec then cuts off I played with the idle control screws but there was no change now theres a screw for the throttle when I adjust that it holds the throttle open a little

well I tried a quadra jet I had in the yard It would not idle just ran at 2000 rpm Im gonna givew up on it today and switch back to the 2bbl tomarrow

<BLOCKQUOTE>quote:</font><HR>Originally posted by Riffers70:
Did you change the accelerator cable? It's about 1.5" too short for the 4bbl conversion. Depending on your transmission you will also have to modify the cable/rod assembly. You might also want to check the spring tension for the return.
Fred<HR></BLOCKQUOTE>

Ok, "duh" question time. Would that also apply for an Edelbrock swap? 2-&gt;4bbl?



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Eric Taylor
72 Malibu 350 (http://www.chevelles.com/showroom/ericsvellepic1.jpg)
68 SS396 basket case

When I swapped my two bbl 307 for a q-jet equipped 350, I had to order a new throttle cable. The two barrel cable just won't work with anything else.

I saw the post where you said you tried a Quadrajet. So, I'm assuming you have a Performer and not a Performer RPM. (As a QJet won't bolt directly to a Performer RPM) If you do have a performer, you need a plate with 2 gaskets to use the Holley on it. Edelbrock sells the plate just for this. Otherwise you can have a vacuum leak at the base, depending on which carb you're using.

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Dave Bradley
www.corvetteforum.net/classics/d1_bradley (http://www.corvetteforum.net/classics/d1_bradley)
'69 SS396 ragtop
'33 3W Coupe
'65 Vette BB Roadster

Something to check would be any vacuum lines. Are all excess holes plugged, all hoses on, none cracked, etc.

ok I checked every thing and I think it was a vacume leak at the gasket I switched back to the iron manifold with the old carb checked the distributor but it seem to be good. my plugs where black and sooty swaped them out with new and still no crank.I was just thinking could it be a carb problem because my 2bbl flooded the fuel bowl through the vents and now has a leak coming from the outside of the carb on the throttle shaft. could the carb be flooding the engine causing it not to fire? because i removed the plugs and can pour the gas out of them. also the engine did fire up with the holly and the quadra jet just high idle. I think im gonna disconnet the fuel lines and try a fire it up by puring fuel down the crb if it acts like it want to fire wouldnt that be the carb flooding the engine?

Ok I put the 4bbl back on and tried to crank it up but got a big back fire that blew the muffler apart WTF Im geting tire of this and Im on my last limb any help ?

Take a break, it sucks working on a car when you are frustrated. One of the key things I have learned in trouble shooting is only change one thing at a time. You need to know if a change is helping or not before you eliminate it as a problem.

I will presume that the plugs wires cap and rotor and in good condition. No intent to offend, just gonna start with the basics...

What is your initial timing?

Double check for vacuum leaks.

As noted above, ensure that the accelerator linkage is not holding the throttle open due to being too short. Disconnect and see if it makes a difference.

Check to be sure that the choke is not staying too closed or not fully opening. Disconnect and see if it makes a difference.

Ensure the idle screw on the throttle linkage is backed off sufficiently.


On the Holley carb, start with the idle circuit at about 1½ turns out, and then reset you idle screw. Adjust them slowly until you get the best idle then reset your idle again. Repeat as needed. This should get you in the ballpark. Hopefully the Holley is in good shape.

Good luck...

[This message has been edited by Bow_Tied (edited 10-03-2002).]

I still get no start so I will be replacing the engine with a 350 l98 anyone know if I can use the exhaust manifolds form the 307 on here and can I use the same motor mounts ?