1985 K20 Smog Pump Question

[DesertBob]

Just bought a truck and I live in a Tennessee County that requires tailpipe only emissions test. My truck is a 1985 K20 with the LT9(M 350) with HD 8600 GVWR emissions. This means no Cat but it looks like it has 2 smog or air pumps. There is no belt and only the upper pump has a pulley. Both spin freely. Truck has AC and is a manual transmission.

Question. Do both pumps need pulleys and if so does anyone have a diagram or picture of this setup.

I was kind of supprised to find the lower pump. Looks like the rest of the emissions stuff is on the truck. Just have to hook up the hoses.

Thanks.