Are their any Parts of a 68 cutals that are not interchangeable with other models?

 

Welcome to the site! I'm not sure I'm following what your wanting to know. The Cutlass body panels and interior are pretty much specific to A-bodies. Then within the Cutlass there are differences such as the hardtop and post doors. The engine itself will interchange into lots of Oldsmobile models/lines. But things like exhaust manifolds will be different between say the Cutlass and Olds 98. What specifically are you wanting to use on your Cutlass, or swap onto some other model?