Hesitation Headache

[Southern Buckeye]

Ok guys,

Here is my problem. Truck is a 69 Chevy with 400 sb. As i was accelerating in a spirited manner away from a light, someone pulled out in front of me and I had to lift off the gas suddenly and brake. Truck immediately began running rough and I had to nurse it home. Long story short, I ve replaced plugs, wires, coil, rotor and pass. side header gaskets in attempt to make it run smooth again. It will run ok but it hesitates when I first give it gas. It also feels like the same is happening even when trying to maintain a steady speed. Almost like it s not getting gas or spark or something. At stop signs it feels like it might stall and sometimes does. Oh, I also replaced fuel filter.

Today I checked and retightened the header bolts before going for a drive and it ran better than ever! Problem is that only lasted for about 10 minutes...after one good push of the go fast pedal, bam, problem came right back. Brought it home and tightened all the header bolts again to make sure back pressure was good. I should add, I only replaced the pass. Side gasket because it was very obvious that was where air leak was coming from. I actually put two gaskets together on that side because someone suggested that would be a good idea with headers. I don t know if that is the problem, just trying to eliminate any possibility. I also sprayed carb with cleaner but I m out of ideas.

Was thinking of changing fuel pump and possibly carb. But before I do that I thought I d ask for some help. Any ideas? I bought truck in January at a auction so I really don't know that much about it s history. It appears a new fuel tank was installed. It also has a Holley 4 barrel. Ignition is HEI. Just trying to give you all what I m working with. I m just learning as I go and don t want to take it to a shop unless I absolutely have to.

If I could just get the darn thing to run like it did for those sweet 10 minutes today, I d be happy!

Thanks in advance for any help provided.

Southern Buckeye
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[ole dollor]

southernbuckeye: sounds like you kicked your 4 bbl's in and they did not close, might try taking off the air cleaner and rev it up and force the secondaries closed when you let off the throttle , might want to spray them down inside and out of the carb....hope this helps.....

[Southern Buckeye]

Is there some special way to force secondaries to close? What I ve done is just revved the carb while I sprayed in carb cleaner. Is what you re suggesting different because if it is than I m on it. And THANKS.
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[ole dollor]

no....i was telling you to do this while the carb was still on the truck....just remove air cleaner....start it up and rev it up to open the back bbl's then close them while you are letting go of the throttle but do this quickly dont over rev the motor for to long....if you already have it off then see if they were sticking open....clean them up real good and put it back on and see if it runs better....

[GASoline71]

I doubt you'll be able to open the secondaries by revving the engine in park.

What model Holley carb, and what intake manifold do you have?

Gary

[ole dollor]

southern buckeye: did you get it running good again...let us know if you are out having fun with your truck....

[dracula4999]

If it has ever backfired thru the carb then it blew the power valve...easiest fix is to by a block off for it.

[rsavage]

Got some dirt/gunk moving around in the carb bowls?

[1quik70]

Power valve is a good thought, might check the timing as well. Something could be hanging up in the mechanical advance.
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