Many people have expressed an interest in adding dual exhausts to their '65-'67 full-size Oldsmobiles.
Some versions of the big cars such as Starfires and Police Apprehenders came with duals from the factory.
Because of the location of the steering box, steering linkage and transmission linkage relative to the outlet of the drivers side exhaust manifold clearances are too tight to pass an exhaust pipe through.
On factory dual exhaust equipped cars, Oldsmobile used a modified transmission linkage rod with a "half-moon" shaped center section to provide clearance for drivers side exhaust pipe.
Since very limited numbers of the 88/98 factory dual exhaust cars were produced, it is nearly impossible to find this rod in the bone yards.

The diagram below gives measurements of the factory rod. This should be helpful in fabricating the rod yourself.
It is recommended that you cut your existing straight rod and weld in a curved center section. This will help insure proper rod diameter and shifter/trans lug position.
The straight rods are plentiful in the bone yards and it might be wise to have a couple on hand to play with while making your custom rod.