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Discussion Starter · #1 ·
Hello there guys. last week I found my head gasket had blown out on my SBF 302. So I tore it down replaced the head gaskets, intake manifold gasket, and changed all of the fluids. I fired it up and it runs only if I stay on the throttle. as soon as you let go of the throttle it dies. I did not mess with the holley avenger 550 at all, so I am a little puzzled as to why it wont idle now. I do not hear any sort of vacuum leak. Anyone out there have any ideas before i start to cry.
 

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If the only thing you changed was the head gaskets and all else being the same the first thing that comes to mind is your timing. If your timing is off it will make that a issues with your carb. I had the same problem years ago before what I know now and rechecking my timing cured my idle issues and back fire issue as well. Make sure you know what your true TDC is and make sure you balancer has not slipped. That would be the first thing to check before anything else.
 

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Discussion Starter · #3 ·
Eric32,

thanks I will double check it today. I suck at finding TDC and dropping the distributor in, always gives me heck. The engine is a 302 roller cam with early 302 heads. being that it is a roller cam engine I am using the HO firing order. maybe that's where the issue lies.
 

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There is a link made from some folks on here on how to find true top dead center. If I was you I would pull the plug on cylinder number one and buy a piston stop from summit or jegs and rotate the engine by hand clock wise and when it stops mark your balancer then rotate the engine back counter clockwise and when it stops again them make a mark on the balancer. Now when looking at the balancer measure the halfway point between both lines and that will be your true TDC line.
 

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When I mean by marking your balancer when it is stopped put a mark on where 0 degree mark is on the timing pointer and then when you turn it counter clockwise to where it stops put a mark on 0 degrees again where the tab points at 0. After both marks are made measure the halfway point and that will be top dead center. I got that from others on here as well as my Haynes manual. I found the link and its below.

http://www.crankshaftcoalition.com/wiki/Determining_top_dead_center
 

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Discussion Starter · #7 ·
Eric32,

Thanks a bunch for the great tips. After messing around a couple of minutes I came to the conclusion that I had a huge vacuum leak. Usually you can hear it but if it big then you do not. sure enough stupid me mounted the carb on the studs with a washer still on one of the studs. removed the washer and the carb seated correctly and now she runs like a champ. At least now I know how to find TDC the easy way. Thanks again
 
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