What can I remove in terms of smog equipment? I think I have a purge canister on the driver's side wheel wheel like a soup can, I also have one on the passenger side underneath the front bumper that is huge like a full on coffee can. Can I strip this baby down to just a PCV valve and cap off most of the vacuum crap? If so, what specifically? I think it's a special California emissions package. Would it run better if I got rid of all this junk?

 

Take it all off. I have a 76 with a 390 in it, and I removed all of it. You'll need to get some plugs for the heads, where the emmissions rails were (4 on each side). I just pulled and capped everything else as well. I'm rebuilding the engine right now, but everything was fine after I removed the emmission system.

 

In general, yes. Your truck is emissions exempt. I think one of those canisters are for venting the fuel system so if you take it out you might have some other things to consider... Point being is be delicate and research before ripping stuff out to do it right. Also, some of the guys with the later dentsides might have interest in the parts, provided they are the same and in good shape, as many of the emissions stuff seems to be hard to come by.

 

Are you in california?

 

Well I have a california smog truck. I took all the stuff off. But if you run it through emissions here in AZ you will have to have it on.

 

The OP is in AZ.

Check your county's emissions regulations. I recall there was another AZ member in here talking about how some counties/metro areas were exempt whereas some were not.

If exempt, be methodical in its removal. Ya might be able to sell it to CA 76-79 Dentside owner who didn't do his/her homework and is now stuck with rig that cannot be registered due to missing emissions parts. It would also put money back in your pocket which is a good thing, right?

 

Where does the EGR come into play in removal? The vacuum line at the distributor? I guess I'm not fully aware of how each of them plays their part in the big scheme of things. Not to be greedy, but if I remove all of this I may keep it for originality in the event I need to sell it. I have collector car insurance on it so I am exempt in AZ.

 

I kept it all and put it in a box. So i have a set to swap onto every truck in case in the future they try and make every vehicle have emissions whether it came with it or not. Then I will be able to swap it from truck to truck.

 

You should not remove the EGR system unless you're prepared to recurve the distributor and rejet the carburetor in the worst case. The engine is calibrated to expect EGR and you can run into issues if you change one without changing the other.

The coffee can is not emissions equipment; it's for your heater controls. If you get rid of it, you will lose your heater controls when the throttle is open wide.

Unless there is a problem with one of these components, the engine will only run as good as it does with everything installed (at best). There is no reason to remove these items other than for aesthetics. In most cases; it's more trouble than it's worth. You may actually see a slight drop in MPG if your EGR system worked before-hand.

 

My vacuum advance canister has 2 ports for vacuum hoses, one on top (vertical) and one on the front (parallel to the ground). Do I cap off the top one and have the front one go to the carb?

 

You may also have an evap system. Leave it hooked up, or you should move the vent tubes away from the engine compartment.

 

Vacuum reservoir ('tomato soup' can sized on OP's truck) for Hi/Lo Comfort Vent System or factory A/C mounts on left (drivers) side fender inner apron.

With either the vent system or factory installed integral A/C: Vacuum controlled heater water valve (D4AZ-18495-A) splices into inlet to heater core heater hose.

Heater only...does not have a heater control valve.
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Evaporative Emission (Evap/Em) System: Unleaded fuel, non vented fuel cap(s).

1973/77: Round steel coffee can sized Evap/Em charcoal cannister mounts on right (passenger) side inner frame rail, could be below alternator or in front of it.

Fuel tank (mid-ship and/or aft axle) has a round hole adjacent to sending unit for Evap/Em vapor valve. Lines route from valve along right frame rail to nipple on cannister.

Vapor hose routes from cannister to elbow on air cleaner.

1978/79: Evap/Em charcoal cannister is rectangular and made of plastic.