1977 351m stock 2 barrel.

I am trying to get my timing set after an engine rebuild in November. I've been monkeying with it for the past month here and there, and I think I have it pretty close with a timing light. So, I bought a vacuum gauge to better set the timing and carb with. But there is an ugly mess of vacuum lines that have a bunch of T's which just go a plugged line. I'd like to remove the mess so I know I'm plugged into a good vacuum line. Which ones can go and which ones can stay? I know I need one for the vacuum advance.

The EGR system was disconnected long ago by a previous owner. As far as I can tell there is no pinging, but I don't know how to tell anyway, as I've never experienced it. Everything sounds good though. I noticed when I rebuilt the carb that someone else had already been in there, as it looked like someone removed the jets before. They may have re-jetted it when they unhooked the EGR but I can't tell. I didn't pay attention the numbers on the jets.

I've read in many of the threads on here that it's necessary you change the jets or recurve the distributor. I'm not sure if it's been recurved or not. Would it need to be if the carb was re-jetted? I'm just trying to get this emissions junk out of the way since most of it is gone or not hooked up. I'm not looking for a debate on the advantages and disadvantages, I just want rid of it. It's not doing anything right now and the truck runs fine. Just trying to get the timing set 100%.

 

You will get alot of differant answers on this one, so take it for what its worth. On my 78 351m all that is hooked up is the advance, and brake booster, all other vaccum lines are gone, I have changed the carb but other than that it's stock,

 

Need:
PCV hose
Vacuum advance line to distributor
Power Brake booster hose
Hot air control valve vacuum line, air cleaner to temp switch, if you are using a stove on the exhaust

Could be more but that's all I can think of that you must have.

 

That makes sense and I appreciate your input. Does the advance line come from the same fitting on the manifold as the brake booster line or from the carb? There is a line that comes from my carb into a T with the advance line that goes into the black box with a bunch of lines coming out of it.

 

the advance comes from the carb, you don't want advance at idle so find the port with no vac at idle but vac as you rev it

 

Excellent. Now I'll tear into it. I wanted to take all the crap off that didn't seem to be doing anything, I didn't want to screw anything up though. But it all went in big tangled circle. A tangled circle, that in the end, wasn't hooked up to anything except the vacuum advance.