Smog tubes (again)

Lets say, I got a set of headers for free, but they don’t have the smog tube which I must have for inspection. I understand these tubes came on factory 80’s Chevys and replacements tubes are available in stores, and can be welded to headers. No store I checked so far has them in stock for me to examine.I ’ll have to special order them. But I don’t know what year/ model/ application to order them for?

.1- What yrs in the 80’s had smog tubes to the manifolds?
.2- Some years had iron manifolds others had factory tubular (short header) manifolds. Do they take the same smog tubes?
.3) I heard some years had the tubes screwed into fittings, others had them welded right into the manifpolds? Id rather weld fittings to my headers, incase the tube ever breaks & needs to be replaced.

Any help thanks. You may e-mail me direct at [email protected]

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