Should I be concerned? - Team Camaro Tech
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post #1 of 5 (permalink) Old Sep 4th, 03, 05:06 AM Thread Starter
Join Date: Mar 2001
Posts: 52

Just did a complete rebuild on my 68 Camaro 327. New everything. After it ran for a week or so, it developed a slight miss, nothing major, but enough to know it wasn't right. It would even backfire slightly through the carb upon quick short acceleration. So checked timing, dwell, points. All O.K.. Then I pulled the plugs and they were black powdery looking. Not oily, just dry black soot and they all looked the same!! Put new plugs in and the car purrs like a kitten. No backfire, no miss. Is this normal on a new rebuild, or should I be cautious of a problem somewhere.
Thanks for any comments. [img]graemlins/clonk.gif[/img]
oldcarman49er is offline  
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post #2 of 5 (permalink) Old Sep 4th, 03, 05:11 AM
Join Date: Mar 2002
Posts: 269

Vacuum leak in intake?

Too rich?

I'm sure more will pop in.

Just finished a rebuild on my 327 too.
67RSM3 is offline  
post #3 of 5 (permalink) Old Sep 4th, 03, 05:19 AM
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Join Date: Jan 2001
Location: Raleigh, NC
Posts: 1,046

sounds like a too rich condition by the way you describe the plugs. A vacuum leak should make you run leaner.. Make sure your plugs are the correct heat range and correctly gapped, especially if you did not build back to stock specs. Look into carb to make sure you are getting a good squirt when you press the accelerator. If you are not, then that gulp of air that you are getting will make your carb pop which could be mistaken for a backfire.
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post #4 of 5 (permalink) Old Sep 6th, 03, 12:43 PM Thread Starter
Join Date: Mar 2001
Posts: 52

Thanks for the imput. I do have a new Holley carb and it seems to be working well.
As well as it is now running with new plugs and no backfiring, I think I am going to drive it for a few weeks and see what happens.
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post #5 of 5 (permalink) Old Sep 6th, 03, 12:48 PM
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Join Date: Sep 2000
Location: Katy, TX
Posts: 482

Holley carbs have to be tuned for the engine. If the plugs are soot black, you're running to rich and you need to jet down the carb. A relatively easy thing to do. Do a search on carb tuning, there is a lot of info here.


1967 Camaro RS/SS 396
1966 Mustang Convertible PROJECT
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