i have been on this topic for a long time. its a 87 el camino with a 305 and a 200r4 trans. I just put headers and dual exhaust on it. My Old qudrapuke was running to rich so i had to get ride of it. So i put on a edelbrock 600 cfm carb and my car doesnt run right at all. So i get ride of the computer and put a HEI distributer on it and still got nothing. I was told to put leaners springs in it and i did that . I think the carb is way to big for my engine so i went and got the same setup as the 500 cfm. I am currently running these settings.Primary jets .086 secondary .095 metering rod. .065x.042 with the blue springs , the shortest ones. I havent touched my vacuum advance on my distributer , and it running really rich to the point when i work on it and if its running i cant even see my eyes burn so bad. is there any thing for me to do else or is it not going to work.
HELP !!!
- Thread starter 87ChooChoo3.73
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Where to begin? First off, throwing money and parts at the problem rarely solves anything. Second, when did the Quadrajet start having issues, was it AFTER you installed the headers? If so, it could be that the O2 sensor was not hooked up right, you have a header gasket leak, or that the air injection system had a leak. Next, a 600 cfm air valve secondary carb would be just fine on a 305 if the step up springs are leaned out a bit. The OEM carb is a 600 after all. Then again, so would a 500 on an otherwise stock 305. Now, the first thing I would do is return it to the factory tune, and go from there. Next, install the weakest set of springs ( opens at the highest possible vacuum setting. I would also check to be sure that the boosters are not dripping fuel at idle. If they are, you either have too much fuel pressure or a stuck needle and seat. Also, what intake manifold are you running?
It was having problems long before i put the headers on i had to change my oil 4 times bc of it. Ill have to check the boosters and needle and seat and if i have a stuck needle and seat wat the easiest way to fix that, and i am using a performer intake from edelbrock.
I just put the stock calibration on it and the lowest springs, and there was a little bit better response nothing good at all tho. But if i were to put in in low and manual shift the gears it runs great. i have the linkage hooked up for the trans could there be a problem maybe there with the 200r4.
Are you certain that you properly sealed the intake manifold to the heads? Also, have you put a vacuum gauge on it? You need to tune the idle mixture screws for the highest manifold vacuum at idle. The vac gauge will also tell you things about the general health of the engine, such as a flat cam lobe that LG4 305's are well known for ( flat tappet models). The vac gauge should have a steady reading. If not, you need to determine why. You also need to go back to basics and set your base timing. If the HEI you used was an old one from a junkyard, it is likely the advance mechanism is in poor condition. I would check it with a dial back light to be sure the timing is steady.
The hei distributer is brand new but i havent touched any of the advances on it mechanical or vacuum and ill will try the vacuum gauge that one thing i havent done yet.
I went thru something similiar to what your doing now it turned out to be that the coil in the distrbutor was working just had a really weak spark.
I'm as big a Q-Jet fan as anyone, but carb design is not the issue here. Either can be made to run well on the engine he has.
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