2nd gen corvette air pump install.
I first saw this idea used a few years ago by "BDC" (2nd gen guru) and have since seen it used a few times.
If you have ripped your stock air pump, AVC, vac rack etc. out. But still have to pass emissions testing. You can do 2 things. First is to mount the stock air pump back into the car. Then run a pipe straight to the cat from the pump. If the car is in good condition and would pass with the stock stuff. It shouldn't have any problem passing this way. It's probably even going to give lower readings then stock. The two problems with this way is 1, if you have a big aftermarket turbo, the stock air pump might not fit back in. 2, you can't drive very long this way without ruining the cat. You pretty much need to hook it up, drive to the test, drive home and unhook it. Which is kind of a pain in the but.
The 2nd way is to use a smog pump from a newer corvette (93+). I think the Camaro and trans am might be the same. The pump has an air inlet, outlet, and 3 wires. Not rocket science. The outlet hose goes to the cat. The inlet line I stuck a breather filter onto. It has 3 wires, red, orange, and black. Give power to both the orange and red at the same time (splice together) and ground the black. You will want a relay as this thing draws over 10 amps.
I crammed mine under the cruise box, between the charcoal can and ABS. I was surprised I could get it in there! It's not too big.
I ran a 10 gauge fused power wire from the battery to a standard 12V relay prong 30. Power out to the air pump (orange and red on pump) on prong 87. I took switched 12v from the wiper harness to prong 86. And prong 85 goes to a 2 wire switch in the car, the other side is grounded.. And Also ground the pump.
The "out" of the air pump is 5/8" but the inlet of the stock split air pipe is 1/2". I bought some 5/8" and 1/2" heater hose. As well as a plastic 5/8" to 1/2" adapter that I found at a local store. The brand "help" makes lots of odds and ends like this. I ran only a few inches of the 5/8" before converting to 1/2. I connected the 1/2" heater hose to the metal split air pipe right below the firewall. Just remove the stock rubber hose and clamp this one on. Don't connect the heater hose directly to the cat!!! I'm pretty sure it'll just melt pretty fast.
By hooking it up this way. The pump will shut off when ever the car is off. While the car is running it's turned on and off via the switch. I have been told by a few people the pump should not be run for more then 10-15 mins at a time as it'll burn itself out. So be carefull
I just recently passed my local emissions with a 3" magnaflow (carsound) cat in my full RB exhaust, and this hooked up to it.