What post #2 said. I made a spacer consisting of two stainless steel v-band flanges with the non-vband sides welded together. It's about 1" though and they are s400 t4 exhaust flanges so not sure if that would help you at all. If you wanted to do what I did, which is not the cheapest route but is reversable considering it's just held on with v-band clamps, you could always shorten the non-vband side of the flanges to your need. Good luck.