# hesitating



## simmons68 (Dec 22, 2009)

Hey guys,
My 1968 gto is hesitating when I gas it. My 400 has just been freshly rebuilt, and ran great for 6 months. One day went to stalling a bit so I replaced the carb (had the original quad. on it) with a 750 edlebrock. Runs better, but still hesitates. My timing is advanced 12, with HEI igitor, new plugs, full length headers. What do I need to check first. It seemed to start this in one day.

Thanks


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## Eric Animal (Oct 28, 2007)

I would retard the timing 4 degrees and see what happens. Also check your plugs and see if you are too lean. Eric


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## Rukee (Feb 8, 2007)

With the engine off an looking into the throat of the carb holding the choke plate open and ratcheting the throttle open, do you see it squirting fuel in from the top on both sides at a good rate??


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## simmons68 (Dec 22, 2009)

*hesitations*

The fuel is squirting at a good even rate on both sides. I'm at a standing still point, I will check the timing though.


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## Eric Animal (Oct 28, 2007)

Could be a vacuum leak....check lines, torque on manifold, etc....


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## Rukee (Feb 8, 2007)

Vacuum advance hooked up to the wrong port?


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## simmons68 (Dec 22, 2009)

*hesitation*

What should my timing be set at with the engine at idle and the vaccuum disconnected? Right now I have it set at 12 advanced with the vaccuum connected. Is this in the ballpark?


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## Eric Animal (Oct 28, 2007)

1967 is 6*BTDC......68 is prolly the same.


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## Rukee (Feb 8, 2007)

simmons68 said:


> What should my timing be set at with the engine at idle and the vaccuum disconnected? Right now I have it set at 12 advanced with the vaccuum connected. Is this in the ballpark?


It's in the ball park. Seriously, every classic engine I've worked with wants it's own settings, and it may not match the book. You could almost throw the timing light away. Just set the timing as far advanced as possable without causing pinging under hard acceleration or hard starting when hot. Then, back the timing off just a bit to act as a safe/buffer zone. You may have to play with the hose going to the vacuum advance unit as to which port on the carb it's hooked to depending on which exact carb you have. Keep test driving and tweeking till you get it right. You want a timing value that will allow for strong power _without_ pinging and also to not start hard. Check the timing with the light only AFTER you street time it. 
Let me know how it turns out.


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## simmons68 (Dec 22, 2009)

*hesitation*

Thanks, I really appreciate your help. I will play with the timing and let you know . Also, my edlebrock 750 has a PCV port in the front of the carb. Can I plug that or do I need to run it to my valve cover? I have heard mixed reviews on this. Thanks


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## Rukee (Feb 8, 2007)

I would run the PCV valve.


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