I'm replacing the gaskets on my lower intake manifold and upper intake (plenum). I couldn't stand the aluminum casting seams and pimples,etc that I see inside the intake, so I'm polishing the ports. What's your opinion on whether it could help performance on a 3.8L? Also would it be a good idea to "match to gasket" enlarging the port openings (I'm not planning on "matching" so far).

 

i did exactly that on darling's car during the rebuild. all i did was removed and smoothed all the burrs and dimples, and gasket matched as well. now since we added a few things in to the engine during the rebuild, it is not noticeable if there were any gains. if there are, they will only be in the 4500+ rpm range. the only thing i used was an aluminum oxide grinding stone, some sanding rolls and a steel wire brush in a dremel. took me under two hours to do and made one heck of a mess