I bought a used but excellent condition K&N cold air intake off eBay and when I got it I did not get the adapter that connects the CAI to the throttle body. Any ideas on where I can get one? I have '03 SS with a 3.8L

I messages the guy and he said he sent everything that goes with it. I went to autozone and bought a 4" chrome but it was too small.

 

Is this the K&N HAI that has the metal box and the filter? If so and that kit was for the W-body platform (which includes the Monte Carlo), it most definitely has a plastic tube going from the TB to the filter. You are missing parts. Here's a link to the kit I am talking about:
57-3045 - K&N 57 Series FIPK, Performance Intake Kit direct from K&N

If the person sold it claiming that is the kit, I would work with him to get a refund or the missing part. If he was simply selling a cone filter, you will need to find a way to adapt it to your need.

 

Have you tried contacting K&N and order the missing part from them?