GM part numbers for the hanger with rubber bits.
14065790 (1st design, 84)
14081994 (2nd design, 85-88). This one is what you seek, although maybe the 84 would work?
There's also the rear tailpipe brackets too.
GM part number 14065797 . Need 2.
Some on ebay. PRICEY though.
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However, Walker makes some too. Or did.
tailpipe bracket is walker part 35125. Looks a bit different than the orignal circle clamps.
hanger is just rubber and bolt kit, walker p/n 36261 for 85-88. The 84 version is walker p/n 35209. Same on either side.
35125
https://www.amazon.com/dp/B000CQBG14/?tag=gbody-20
35209 (1st design hanger)
https://www.amazon.com/dp/B000C8ZAMS/?tag=gbody-20
Walker 35261