NECESSARY Q-jet vacuum lines needed

[Old60Driver]

Finally got some time to tinker. Got some headers installed (removed the air pump) and was moving on to cleaning up the 3.641 miles of vacuum lines up on the intake. I know I need vacuum advance, brakes, cruise (when I get around to troubleshooting that), but what else do I need? There seems to be a diaphragm at the back of the carb that works in some way with the secondaries. I'm sure I need some vacuum there.

Anyone have a quick and dirty diagram of the absolute required lines?

Thanks!

Edit to add transmission modulator...

 

[DanMcG]

Can you post a pic of the carb?

 

[Ellie Niner]

Also a picture of your emissions/vacuum hose routing diagram would be mucho helpful. I'm presuming this has Electronic Spark Control and an M4MED carburetor? The diaphragm should be to lock out your secondaries when the engine is cold (choke is on).

 

[Old60Driver]

Thanks for your replies!

Trying to get some pictures uploaded now, but I think I have it figured out. The diaphragm in the back I was referring to is the rear vacuum break. I was concerned with what type of vacuum it needed, manifold or ported. Decided on manifold. The thing was, there was a bazillion little check valves and miles of vacuum lines that just, well, cluttered things up. I'm getting everything prepped to pretty her up a bit with a new intake and some chrome bits that the wife bought for me (she's awesome like that), so I wanted to clean up (get rid of) the stuff I didn't really need.

I tell ya, after removing all of the air stuff, and slapping the headers on, she sounds damned amazing. And the off idle throttle response is MUCH better now. At least in park, that is. I've yet to run her under load, but I'm taking her to get the headers/exhaust welded up this morning. I'll let y'all know how she runs. AND I'll see if I can post some pics!

Thanks again!

 

[75gmck25]

In my experience the, vacuum break lines (there may be both a front and a rear vacuum break) just loop back to nearby ports on the carburetor itself. The lines are usually only a few inches long.

The minimum you need is one small manifold or ported vacuum line on the front running to the distributor advance (cap the small port you don’t use), one large nipple on the front for the PCV, and a large threaded fitting with metal pipe on the back for the brake booster.

If your truck was converted to electric choke you may also find a couple more fittings that look like small vacuum connections, but are actually left over from removing the hot air choke. They can just be capped.

 

[Old60Driver]

Roger that, thanks 75gmck25, that's what I was thinking as well.

'Preciate the info!