My 85 is a filter in the carb it's self, and i'm pretty sure that 49 states had the same basic setup.
I don't know what California had, their rigs may have been fuel injected already.
If I was planing on keeping the 2.8L I'd probably add a second in line fuel filter, along with an electric fuel pump.
There was kind of a restrictor plate in the throttle body, but mine disapeared when I did the engine re-build, along with the rest of the polution control junk.