Please Help, I have searched and googled everything I can think of and I can't find any info. I am trying to set up my 3x2 for my SBC and can't figure out how to run the Distributor, TH350, and Brake Booster Vacuum off the 3 Carbs. As you can tell in the first photo the center Carb seems to have the part were you would run the distributor vacuum closed from the factory as you can see in the photo the end carbs are open. Will this on the end Carbs nee to be closed/plugged? Also in the second photo the base has a fitting on the bottom but I wasn't sure if I could run the brake and distributor off that but then there does the trans go and can they both be spliced to the same one. I am thinking about running without a brake booster but then I still need a line for the trans and distributor. In the last photo there is a tube that is above the base fitting that is connected to the choke. I could go with electric choke if that will work for the distributor. So I am stuck please lead me down the right path and yes I know another SBC in a Hot Rod.
If you have a vac port in the intake both the booster and TH350 should plug into that or carb base . The Dizzy should go on the primary carb base on the front of the carb in the original position from the factory, really can't see the port in your pictures . Have fun!
This intake doesn't have any vacuum ports and as you said it seems the center carb I have doesn't have the front port like it should. In the first photo the center carb in closed from the factory it seems.
I've set up a couple sets of these, so I'm not an expert, but if I was doing this with the carbs you have, I would swap the center carb body with the rear carb. Leave the tops and bases where they are and swap the main jets. That should give you a dedicated distributor vacuum port. BTW, all of the 2G carbs I have seen have this port set up for constant vacuum rather than ported, even though it is located above the throttle blades. The ports are contected by drilled passages to below the blades. The booster and the T350 could be plumbed off of the rear carb base fitting. Unless someone has plugged the base ports, this should give you constant manifold vacuum. This port SHOULD connect to both sides of the intake runners below the throttle blades. Also, you need to plug the front carb distributor port since this would be a big vacuum leak. Mike
They are easy carbs to work on. Very simple internally. Be carefull when tightening the top cover screws. The metal in the bodies is soft. Nearly all of the center body castings I have seen have the power piston vacuum passages drilled, except for true tri-power end carbs, which have no power valves. Yours appear to be regular 2G's, so everything should work OK. Mike
Mike thanks for the tip once I am released from duty today I will tear into it and see if I can't get it swaped
actually either of the ports that are open go straight down through the body and come out below the butterflies in the base. This is where GM got the manifold vacuum for the vacuum advance. Even though its not on the center carb it will still see manifold vacuum because it comes out below the closed butterflies. Spray some gum cutter in there to see where it comes out. The center carb base has the large opening that I use for the PCV valve the booster is usually connected to the manifold because it doesn't pull any thing through it like a PCV valve. I tie my PCV valve in here so that you do not lean out the mixture to any one cylinder. Yes the unused vac adv port will need to be plugged so that it will start. I've never seen the un-drilled vac adv port before but you probably don't need it
Tommy thanks looking at it and your photos I think I got it Thanks again for the help. And saving me from trying to take apart the carbs
LARRY AT HOTRODCARBS.COM MAY BE ABLE TO HELP. HES A MEMBER HERE. AUTOMOTION http://www.jalopyjournal.com/forum/member.php?u=155854
Ok a new question has come up! On the two end carbs there is a GAP in the gasket between the carb and the base. Is this gap suppose to be there or am I in need of new gaskets?
It's probably a patented name but the term has become an accepted name for a spray can of carb cleaner. It has a straw taped to the side of the can that can be stuck into the nozzle so the straw can be put inside small ports and when it is sprayed you can see where it comes out. I get mine from Walmart. It's not Gum cutter but it does the same thing and it's cheaper. I think every real hotrodder should have it in stock along with penetrating oil.
Impossible to answer this one without knowing the identification number of the carburetor. Some carbs were designed to use the vented gaskets, some were designed to use non-vented gaskets. YOU WANT TO USE THE CORRECT ONES FOR THE CARBURETOR. Using vented gaskets on carbs designed for non-vented can give problems. Using non-vented gaskets on carbs designed to use vented gaskets WILL give problems. Try this link: http://www.thecarburetorshop.com/Ventedgaskets.htm Jon.
Jon thanks when I get home from work I will check the number and see what I have man I am learning alot on these 3x2 Rochesters.
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