I got a Edelbrock performer #1406 carb for Christmas and I have it on and my truck runs a great deal better (damned QuadraJet...) anyway, just to make sure of things... Question the first: The vacuum port, I had the distributor lines hooked up to the timed vacuum port to begin with, ran fine but not spectacularly. Then I hooked it to the manifold vacuum port and it seems to run much better. I blocked off quite a few vac. lines during the install, and removed the EGR since it was in the way, and when idling there's vacuum present at the hose. Dumbass me forget to check the old carb vacuum port before tearing it out. Question the second: What's the best way to set the Idle mixture screws. The directions Edelbrock confused me, so I just leaned it out till it sputtered and riched it up a turn and a quarter on both screws. Does this give me a good setting? Question the third: I need to get the best fuel economy right now, anyone know offhand what rods and jets would do that for me? And finnaly what I got: '85 GMC Jimmy with a new 350 crate, Edelbrock Performer 1406, stock everything else. And I do most of my driving at and around 6000 feet above sea level.