Although they are a Pontiac part supplier, back in 2003 I found the rear exhaust hanger straps at Performance Years, Inc. in Hartfield, PA. Their web site is: http://pysales.com
and exhaust system parts are at: http://performanceyears.com/exhaust/. You can either click on the Trans Am/Firebird on line ordering icon and then search for part number RFE114. or simply go to: http://184.108.40.206/iwwidb.pvx?;multi_item_submit
, click search and enter part number RFE114. See attached Word document. It has an imbedded picture of the hanger.
Their description states: 71-74 VENTURA & 67-69 F
. List price is $11.00 plus shipping.
I purchased 3, although I only needed one because they were/are so hard to find. One I installed fit properly. Other two are hanging on the garage wall for spares.
I would consider giving them a call.