Spark Plugs What is wrong?

[B. W.]

Originally Posted by 53chevyforever

Okay...just bought the truck...running this way...compression test already done
and is good...I have had all ac plugs and made no difference...both carbs run
perfect on my other truck...1406 stock eddy and stock600 holley.
The cam already in engine...214 at .050 and 456 lift. One is a new msd street fire and the other hei is good I know runs perfect..been carrying as a spare...fires right up and idles well..its mid range and low on power almost like a wire is off...but not quite. Really does not smoke. Throttle response is good...fuel pump has 5 pounds of pressure. So you tell me?

OK, so you know what is good, you can eliminate those. It narrows it down to a timing issue or a mechanical issue. Do what Geezer said: bump up your initial timing (I'd dial in as much as you can, if it begins to "hard start", back it off a little. Also confirm your timing mark.

If it has run like this since you bought it then you are chasing someone else's rabbit. There is a possibility that the cam was installed out of time. What heads are on it? If the heads have dual springs I have seen one spring break & the engine runs fine but doesn't run well up top. (the remaining spring keeps the valve operating & quiet, but "floats" at higher RPMs)

I'm hoping it's a simple timing issue, sure you are too!