1978 Chevy Silverado Engine performance slugish

Tiny
RANDELL86
  • MEMBER
  • 1978 CHEVROLET SILVERADO
  • V8
  • 2WD
  • AUTOMATIC
  • 68,000 MILES
My truck has a 454. When I accelerate it moves normal. But if I floor it, the rpms go up and then it seems like it is boging down. I replace the spark plugs and wires and changed the oil. I have a 750 cfm holly domination on it I thought I was getting to much fuel. But Iam not sure at times it back fires.
Sunday, February 28th, 2010 AT 7:14 PM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
If it is a 454, then 750 cfm isn't too much. I ran one of them on a 383 back in the day. I have a couple questions for you, if you remove the plugs, are they white or black? Also, have you tried adjusting the air fuel mixture? Finally, have you checked to make sure the fuel pump is producing enough volume?

Let me know.

Joe
Also, if you haven't already, make sure there are no vacuum leaks. And if I remember, the secondaries are actuated by vacuum. Let me know. It's been awhile.
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Sunday, February 28th, 2010 AT 10:18 PM

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