Guys, I recently bought a 71 skylark that has a 455 swap. Dude said this 455 was rebuilt. Somebody converted it to HEI style dist., and it has an edelbrock 1407 carb, on a stock manifold. The heads have 73 stamped on them. I cant get this thing to idle low. The idle is very high. The vacuum advance for the dist is routed to a 3port vacuum inlet that is bolted into the front of the intake manifold. the other 2 ports of this unit had a vacuum line to either side of the carb. From what I've read this is wrong. I feel the line to the dist should go to the left (pass side) of the carb. but that would leave nothing on this vacuum tree on the front of the intake. Can somebody post/ link to a proper vac. diagram for 71? The only emissions device I can find on the car is a charcoal canister.
First, there is no reason to use that vacuum tree, it serves no purpose other than emissions control. All you need is a single vacuum line from the carburetor to the vacuum advance. You can use ported vacuum or manifold vacuum to the vacuum advance canister, your choice. If it is connected to manifold vacuum, you will have vacuum advance at idle. This will raise the idle speed. You can try a ported vacuum source and see if that brings the idle down. Second, the Edelbrock carburetor is a square bore carburetor. The stock intake takes a spread bore. It is necessary to use an adapter plate to avoid a very common vacuum leak. In any case, a Q-jet will run much better than the Edelbrock. Read my thread on Timing in the FAQ forum. http://www.v8buick.com/showthread.php?t=63475
Larry the carb is sitting on an adapter about 3/4'' thick. I think this is the adapter you speak of. I will plug that port and go to one line to the dist, and see what I get.
It's not a diagram, but it's my 71 Skylark converted to a 455. The only vacuum line being used to the advance for the dist, the vacuum brake for the secondaries and the vacuum modulator for the tranny.
