I have a pair of Hedman Hedders part number 58150 for sale. I got these from a friend of mine who decided to sell his G-Bodies and unload all of his parts. They are uncoated and painted black. They feature 1 3/4 inch tubes and a 3 inch collector. These are designed for 1968-76 Delta 88, Vista Cruiser, Cutlass, and 442s with the 400/425/455 engines. He tried to use these in his 1985 Cutlass with a 455 engine swap without success. Several tubes were clearanced to make them fit. Otherwise, I don't think they were used on a running engine.
Asking $100 plus shipping. These are $299 from Summit, $284 from Jegs, and $289 from Amazon.
My finger points to the dented tubes in the pictures.

 

Sold.
Thanks.