On a 1986 trans am with carb, where does the AIR pipe on the cat get connected to in the engine bay?

I believe the car had a hard line that when from the AIR pipe on the cat, but it kind of fell off in my hand while removing the exhaust, and I'm not entirely sure it was even hooked up in the engine bay.

Also, does anyone know where you can get a replacement hard line?

 

It goes to the air diverter valve near the air pump. One side goes to the exhaust manifold air injection lines, the other down to the cat (there's also a muffler/diverter thing built into it which gets nothing connected to it).

When the car is running in open loop, air goes to the exhaust manfolds. When it's running in closed loop, air is sent to the cat (to prevent scewing the O2 sensor readings by blowing air in upstream of the sensor). Under certain conditions (like lift-throttle overrun) it diverts to atmosphere.