Quote:
Originally Posted by clyde72
We have a 57 long bed 4wd at work with a 400 smallblock that I put a Holley on a few years ago that runs pretty good, maybe I should grab that carb and see if it makes a difference
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Carburetor issues very seldom cause a particular cylinder to misfire. Seldom enough that carburetor replacement should be far down on the suspect list.. Doesn't miss until the engine is up to operating temperature is a good clue.. It's probably a lean miss due to a vacuum leak on one of the runners. During initial start up and running, the choke is partially closed creating a rich condition thus "masking" the miss. Check for any cracked, broken, or disconnected vacuum hoses.. Don't forget the vacuum source for the transmission modulator valve if so equipped. Intake gaskets are another source for a cylinder related vacuum leak.
{EDIT} Go back and properly adjust those valves before you damage a lifter, valve stem, or rocker arm...