Well I have a 350 70 buick eng. with a 4 barel quardjett carb. well on the front it has 3 vacuum lines and one in the rear. What should these get plug in or should I block them off? I've put the eng. in a 85 regal. please help I think this is why my buick is still not running right.
I can't tell you weather to plug them off or not that will be up to you. I can tell you what each one is though and this should help in your decision on what to do. First the vacume on the back of the carb. this vacume is for the your vacume cannistor that controls your heater and a/c controls. If you car doesn't have vacume operated controls than you can plug this off. It is a manifold vacume sorce. Now looking at the carb from the front most Q-jets (not all) will have three vacume ports. One in the middle of the carb on the left hand side is manifold vacume. This can be used for a vacume advance dis. if you like. Depending on the Q-Jet there will be another vacume port on the left side either on the top or the bottom front (not both) that is used for the choke or secondary pull off. This should already be plugged into a vacume cannistor. Now on the right side of the carb you have two more vacume ports. One in the middle of the carb on the right that is Ported vacume (no vacume at idle and pegressivly more vacume as engine RPM increases) can also be used for vacume advance if your engine can handle it and you have to set your advance to stock settings. And there is one more vacume port in the base plate on the front which is supposed to be hooked up to your charcole cannistor that vents your gas tank. If you don't have one of these on your car you can plug it. It is manifold vacume. I hope this helps and isn't too confusing.
