Just bought a 79 4x4 and the motor runs but seems to idle high and not smooth.
Will also backfire some.
From what I know, the motor is a reman 20r with a weber 32/36 and crane electronic ignition.

I believe that I have correctly plugged all the vacuum lines and that has seemed to help tremendously.
The truck also does not have a muffler and is running a header to a glasspack.
I'm suspecting there is another leak somewhere.

Any other things that I should be looking for?

Here's a pic of the engine bay, I'll post some more detailed pics when I get then today or tomorrow.

 

get a bottle of carb cleaner and spray it around the base of the carb where the adapter is, alors where the intake manifold meets the head, if the idle drops or stumbles you have a vacuum leak there and may be the cause of your problems, also if you have the two piece redline adapter for the carb they are known to cause vacuum issues. Keep us updated!

 

I'll definitely give that a shot, it looks to be a pretty half a** job at desmogging.

 

My distributor vacuum advance only has one vacuum hose. Most pictures I notice two.
Also facing the engine bay from the front, something looks to be missing directly opposite of the distributor. Looking at diagrams, I'm not sure exactly what this is, in the desmog tutorial, I notice that this was not removed.
In the picture below, it is directly to the left of the 20r sticker, kind of shiny looking.

 

That is the fuel pump, I think on most if not all 79 models had an electric fuel pump instead of a mecanical one. And if there is two ports on your vacuum advance put only one hose you should put two.

 

Thanks that helps a lot on the fuel pump. Makes sense now.
I also believe that I need a fuel pressure regulator to make the weber run properly. Would that be correct?
Only 1 vacuum port, I'll dive in with more pictures as soon as this weather lets up. Hopefully tomorrow evening.

 

That's what I heard too, I don't have first hand experience on weber carbs yet, so I can't tell you precisely where to adjust. This is what I am buying: http://www.summitracing.com/int/part...-804/overview/
and gauge: http://www.summitracing.com/int/part...0001/overview/

With clear detailed pictures some people here might point you to some things wrong.

 

You don't need a regulator if your electric fuel pump puts out the right pressure. But if you have a manual fuel pump you need a regulator I believe.