Hi,
as restoration of my third gen is slowly moving towards the end I need to buy new cat.
My question is if I buy new cat that doesnt have smog pump air inlet hole can I run it without smog pump? Or do I need to get cat with smog pump air inlet?
Also how is with the emissions?

Thank you for help

 

Just get a cat with the inlet.

The smog pump pushes fresh air to the cat to make it more efficient.

 

GM actually admitted years later that the air pump was needed to dilute the exhaust to meet emissions standards at the time.
I don't know if your car came with a pellet type of cat converter or the better honeycomb type. You want a high flow honeycomb type.
Depending whether or not you have to pass emissions where you are located, and to what degree of restoration you are going for, if it were me, personally I would get the cat without the air tube and ditch the entire air pump.

 

Thank you both, I will go with cat with inlet, just to be sure I will pass emissions test.