An example of the AC "KV" kit 1003(Chevy V8) with various connector options.
I do not have a picture of the AC "CV" kit.
From the AC catalog page for GMC (attached), it looks like the KV1004 kit and CV hose is required in California (black triangle).
If you live in California you would need this before you could pass inspection today.
Attachments
Closed Kit.jpg (86.14 KB, 242 downloads)
KV Kit.jpg (20.38 KB, 242 downloads)
GMC.jpg (268.06 KB, 229 downloads)

"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."