Not aware of any with a 1.75" ID, but you could pickup a set of these:
http://www.cbperformance.com/product-p/2802.htm.
If you take a 1.75" pipe, sharpen the edge like a knife, you can punch the opening to 1.75. You may be smarter to buy the smaller sized compression gaskets, giving you more material to punch out.
-Dave