This is a new old rear muffler that is Arvin brand and part number 1659.  This fits 1956 Oldsmobile 88 or 98 with dual exhaust for the right side (sorry I do not have the left side).  This is 38" long overall and muffler portion is 33".   Part is new never used and in excellent condition as seen in the close up photo.  Local pickup allowed for this item.  Otherwise buyer to pay shipping.