Smog and Cylinderhead Question

[davbell22602]

Fuel evap systems don't need special heads.

Air injection systems require different exhaust manifolds.

Post the links where you got the price difference for smog & non-smog heads.

http://shop.advanceautoparts.com/we...Cylinder-Heads_20530061-P_246_R|GRP60012_____

http://shop.advanceautoparts.com/we...Cylinder-Heads_20530062-P_246_R|GRP60012_____

 

[skysurfer]

Looks like the small blocks used an air injected exhaust manifold in their IMCO smog system.

The big blocks had a different system called Thermactor that injected air behind the exhaust valve via a drilled/tapped port in the head to which a pipe/manifold system was attached.

The only difference I can see between a "smog" head and "non-smog" is whether or not it has the air port tapped and drilled. I doubt Ford would have designed a completely different head for emissions, too much manufacturing costs.

If you don't have an air pump on your truck it's a non issue.

 

[davbell22602]

Looks like the small blocks used an air injected exhaust manifold in their IMCO smog system.

The big blocks had a different system called Thermactor that injected air behind the exhaust valve via a drilled/tapped port in the head to which a pipe/manifold system was attached.

The only difference I can see between a "smog" head and "non-smog" is whether or not it has the air port tapped and drilled. I doubt Ford would have designed a completely different head for emissions, too much manufacturing costs.

If you don't have an air pump on your truck it's a non issue.

Ok Thanks. I dont think I'm supposed to have a air pump. Just a standard carb engine.