Did a little more searching and came up empty, can't find a vacuum leak. I am running an Edelbrock performer series 4 barrel carb and I did a check around the base gasket and checked the mounting studs just to be sure they were still tight. No power brakes so that is out and no auto. trans. There are only 2 vacuum lines on the truck, one for pcv and one for advance and both are good. Pcv is working. The tube on the carb for the vacuum adv. hose is solid.

I did notice something though. It isn't the vacuum advance hose that makes the engine stumble but rather my hand. Let me explain. I have been doing the work on the truck with the breather off the carb so I would have better access to certain areas such as the dist. area and the vacuum hoses on the front of the carb. When ever I reach into the area in front of the carb I get the same engine stumble as before but I am not touching anything. I tried it several times and it only happens when I place my hand in front of the carb area which just happens to be where the advance hose connects. Is this because my hand is blocking or disturbing the air flow into the carb? Is it normal?
I tried touching the vacuum advance hose near the dist. area and nothing happened. I also disconnected the hose from the vacuum advance and plugged it off and it made no difference to the way the engine was running.

I tried adjusting the timing by turning the dist. just to see if maybe the timing had magically changed but that did no good either.

I am grasping at straws here but does it sound like a carb problem? I don't think it has trash in it because I have always used an inline fuel filter and I purchase my gas from only one place for both my trucks and I am not having a problem with my daily driver.

Ralph Davis
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Old trucks never die, they just find a new home.