i am not positive about the 73 carb because that is a more emission carb than a 70 i believe. for non emission carb you want the lowest nipple or port. you want the one that is closest to the manifold. ask some one who knows what the diff is between the 79 and 70. good luck jim
There are 2 types of vacuum, ported and manifold vacuum. If you uncap a manifold vacuum source, it will create a vacuum leak and it will hiss. A ported vacuum source will have no vacuum at idle and increase as you open the throttle. The manifold vacuum source is not always the lowest one although it can be. I run all my vacuum advance to manifold vacuum. I think it reacts quicker to changes in throttle opening. Emissions era engines used ported advance.
Doug: Thanks again for pinpointing the problem. The pinchy clamp barbs were oriented toward the opposite hose. How stupid! The hole was in the smaller diameter fuel line which must be the return. Once I get the tune-up figure out, I will replace the hard lines as well. Back to your regularly schedule tune-up puzzle!:3gears:
Here's a little 411 in the event anyone else has to replace these hoses. A LOT of fuel will be lost when the supply line is interrupted. Have a small gas can with flexible pour spout ready when you pull the old line.
