Hi - I have a pair of secondary AIR pipes w/ check valves for a 2001 LS1 (ws6). I had the trouble codes P1415 and P1416 just before emissions and had to replace the parts on short notice. Eventually, I was able to clean the originals and restore them to working order, so I have both sides, and both work. These retail for $75 each at the dealer. I have one extra check valve I can include as well (i had trouble removing one from the original pipe). please send PM if interested. can ship, and will accept payment via paypal bank transfer (no credit cards, I don't have a business account there). buyer pays actual shipping cost and can choose the carrier. thanks.