1978 Chevy Corvette lack of power

Tiny
KIMTHALER
  • MEMBER
  • 1978 CHEVROLET CORVETTE
  • V8
  • 2WD
  • AUTOMATIC
  • 74,000 MILES
I am the original owner of this 78 Vette.

I changed the plugs and wires and found that the drivers side bank had clean plugs. The passenger side had the head of the plugs almost gone. The drivers side exhaust (no crossover pipe) had much less exhaust output than the passenger side exhaust. I had the pipes behind the dual catalytic converters replaced including the mufflers and they told me the cats were both good. Power 0-60 used to be around 7.2, now it is around 9.5.
Help!
Kim Thaler
Saturday, August 28th, 2010 AT 10:25 PM

6 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Is the engine missing or running differently other than the power loss? Have you checked engine compression? I ask because of the difference you explained with the plugs. Also, has the carb had any work done to it?
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Monday, August 30th, 2010 AT 9:03 PM
Tiny
KIMTHALER
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  • 4 POSTS
I really do not notice any specific missing. In fact, it passed inspection in California, but the guy doing the inspection was scratching his head why one side of the exhaust had less output (maybe 50% less). I only run the car around 500 miles a year. I last rebuilt the carb around 15 years ago. I did put in a new distributer about 5 years ago and it did run a bit better.
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Tuesday, August 31st, 2010 AT 10:01 AM
Tiny
KIMTHALER
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No, I have not checked the compression test in a very long time (maybe 20 years).
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Tuesday, August 31st, 2010 AT 10:03 AM
Tiny
JACOBANDNICKOLAS
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Based on how the plugs are, you may want to start there and have the air / fuel mixture adjusted on the carb.
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Wednesday, September 1st, 2010 AT 10:47 AM
Tiny
KIMTHALER
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  • 4 POSTS
I beleive your response makes sense. I will try the carb adjustment once I get over my knee surgery. I did buy a rebuild kit a few years ago so I might try rebuilding the carb or just buy a new one.
Thanks!
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Friday, September 3rd, 2010 AT 12:15 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Let me know what you find.
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Friday, September 3rd, 2010 AT 12:55 PM

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