6066 (1960-1966) GMC Truck Club

Quote:

Originally Posted by snazzypig (Post 66595)

Hi Jake, Welcome to the club. I've seen some of your videos and you really do good work!
As to your question about jet numbering, all I know is that the sizes increase with the numbers, and some people have gone to larger jets with some success. Also, I have a Bendix/Stromberg catalog that shows your carb number 23-120 is correct for your 5000 series with the 351.
Concerning the loss of power, since you say the carb has been rebuilt before, I would look there first.
The power system, which includes the vacuum power piston, may not be working properly. Make sure the gaskets above and below the throttle body aren't blocking the small opening (vacuum channel) leading to the intake manifold.
Not trying to underestimate your ability, just some things I would check if it were me.

Thanks Snazzy!

I was able to open up the jet to the .057. They were at .053-.054. My tip cleaner for the torches... one of the wires was .057 on the file section. Ran the jets down over it and opened them up nicely. Worst that can happen is I have to buy another set...

Thanks for checking the carb info! I can find some online but there doesn't seem to be a lot on the GMC Strombergs from what I've found outside of this site.

I was messing around with it some today and decided to venture into the power piston. Turns out the small round plate that sits in the carb body and holds the piston wasn't seated all the way down. So I might have been loosing some vacuum there. I pulled the piston out, looked alright. Can't tell if it's worn or not. Reassembled and the plate went back in and seated nice. I'm re-intalling the governor on this go round so I spent some extra time checking on the vacuum channels. As far as I know they all look to be clear and free of the gaskets.

Don't worry about it, I don't know everything! If I did I wouldn't be seeking help from you folks...