Smog Control Tubes

[sb4boys]

I am rebuilding my 68 Ford f-100 360 engine and wanted to plug the smog tube outlets on the heads. Would this do any harm to the engine or create performance issues?

[Ohiotinkerer]

Nope - did it on mine without any difference. All that did back then was pump air into the exhaust to "reduce" emissions back in the dark ages of pollution control.......pretty much a joke........

If you have a NAPA store with older guys working there they should be able to get you the threaded plugs we used for years to eliminate that garbage........

[Manny]

Plug them up no problem. If you can find some different heads you would get better power, or port those up and grind the thermactor humps out while you got the heads off.. Them old smoggers were again a patch at best.

[71Fe2O3]

The idea was to pump air into the outgoing exhaust-old engines run rich, so one way to reduce hydrocarbon and CO emissions is to introduce air into the exhaust that converts some of the hydrocarbons into H2O and some of the CO into CO2. This allowed manufacturers to meet the relatively lax emission control standards of the day. The early systems, primitive and clunky, robbed engines of power and probably didn't cut emissions by very much.

Because excess hydrocarbons are detrimental to catalytic converters, air injection is also used on modern vehicles, though in ways that are more elegant than the old "smog pumps." It surprised me to see that you have this in a 68-I didn't know they had them that early.

To make a long story short, you can disable what is in your vehicle or swap your heads. FE heads are plentiful.

[Ohiotinkerer]

Another thing I just thought of - do you also have 2 ports on the vacuum advance on the distributor? If so disconnect the rear hose and plug off the ports on both ends - this was also a pollution control designed to retard the timing at cruising speeds (highway driving) and recheck your timing - also made a big difference on mine......

[Ohiotinkerer]

It surprised me to see that you have this in a 68-I didn't know they had them that early.

It seems to be more common on trucks that were built in California - mine was built in San Jose and it had all that garbage on it but stock bumps I've seen here in Ohio doesn't have it on them..........

[colnago]

It surprised me to see that you have this in a 68-I didn't know they had them that early.

It seems to be more common on trucks that were built in California - mine was built in San Jose and it had all that garbage on it but stock bumps I've seen here in Ohio doesn't have it on them..........

Thank goodness, Cali didn't do it in '67. Leastways, if they did, then a PO removed it all before I got my bump. Mine was also built in San Jose.

Joseph