Several people have asked about mufflers for the Jetfire Turborockets.They are getting hard to find! The dual outlet, single inlet mufflers offered by Oldsmobile were for the Cutlass 4-bbl (that is the way GM lists them even though all Cutlass’ were 4-bbl) and Jetfire. The difference was the size of the inlet pipe. The Cutlass muffler was 1-3/4″ inlet and Jetfire was 2″ inlet. They both are 1-1/2″ dual outlets. All that I have seen were stamped “GM” and made by ARVIN.
Jetfire-GM part #380173. Cutlass-GM part#582028 and 585616.
I couldn’t find a dual outlet muffler for my Cutlass after a few years of searching. I ended up having Waldron’s exhaust make one for me. This is an option if you can’t find anything NOS. It has welded ends vs crimped/folded ends but fits exactly the same otherwise.
Recent questions regarding Cutlass exhaust systems sent me searching for this old post about mufflers and dual exhaust added to Cutlass cars. Here is the muffler info brought forward. It would be cool to have a search method on our website.