According to the 1987 book "How to bypass emission controls" with a c4 on the cover no less, gutting the air pump is discussed. I took mine apart and whereas they talk about the "shaft" my 91 has a different mechanical system that appears to be tamper proof.

It should have a drum, with fiberglass fins inside, attached to a stationary shaft.

The drum rotates, forcing the fins to rotate around the shaft.

There's also some slider pieces in the drum slots to reduce friction.

The fins don't fit out of the drum, so you have to carefully smash them to bits with a screwdriver to get em out.

Also try and fish out the little sliders so they don't come loose and jam up the pump later.

The drum will stay in use on your gutted pump.

That always seemed like a hassle to me. When it was time for the headers, I went ahead and completely deleted the air pump. With a little creativity, you can move the alternator up, bracket it to the engine, and your all set. No gutting or pump required. And if your really concerned that the Inspection guys by you will notice (and believe me, they don't even know what they are looking at half the time) you can pickup a "air pump delete" label from an Impala SS, which is supposed to make it "legal" (wink, wink)

DG

Thanks for the info, C.C. The procedure went smoothly. The pump was making a noise, gone now. I did a series of 7 runs. My Gtech tells me I gained a solid 1/10 sec. on 0-60.