My wife's 85 lt250r has an fmf exhaust and boysen reeds and supposedly had the ports cleaned up.would getting a port work make much of a difference with this year quad.
It will make the same difference now as it did in 1985 when they were new. The big question is: what type of power level or what bike are you expecting this ported quad to outperform?
It will take more than just porting for the 85-56 to outperform the 450 four strokes that has a good pipe and a good intake/air filter setup.
How far you want to take this engine depends upon your budget.
It will take the "right" porting, head mods, piston mods, a larger carb, a better pipe to get this engine up to 43 to 45 HP. An engine at this level will not run on pump gas.