Ummmm can anyone tell me what these 2 vacuum ports are for?? I use the 3rd one at the base of the carb for the modulator valve. The port on the left is under the choke and take a 5/16th's hose. the other is on the primary metering block and looks to take about 1/4" hose. I have nothing connected to them and run the engine it seems to run fine, but after I shut off the engine smoke comes out of the larger port on the secondary side. Thanks for the help!



Full size here!

 

if you're not using them, get some caps and cover them up so they don't draw in air and make the motor run leaner than it should. if you can't find caps, just use a short piece of hose with a bolt screwed into one end of it to plug them up. you might have to adjust the idle screws once you have them capped off too.

 

the top one is used for vacuum to the dist. if you have a vacumm advance thier so no vacuum there until you open the throttle..like roundy said if you don't need it plug it off......the one at the base most people use for a pcv valve...the other one can be blocked off....I can't beieve it even runs..you'll have some tuning to do..that's a fairly old 600

 

thanks a lot!!! that's what I wanted. I have an MSD Billet Dist so I won't need the vacuum advance. and I'm running breather filters on both valve covers so I won't need the other. as for that caps I work at an auto parts store can't be that hard to find some. thanks again for the help!!!!