I have never been one to just take an engine to the max just because it can be done..I believe in longevity..any refresh/rebuild that requires cylinder attention should only be addressed as what needs to be done to correct the problem with mininum effect to long life. Same with shaving heads and blocks..this is reserved for the eventful need to correct for slight warpage...unless you building an all-out racing machine, the results in going max versus the inprovement you will see on the street is just not cost effective. Better iginiton, better breathing (intake/exhaust manifolds) higher lift cam with longer duration and improved carburation..will net you some pep without sacrafice to the metal in your motor. Mind you you will lose headroom for lift with milling of head and block.
Of course..if you just got to do it..then hey..go for it..it just an old engine..rodders throwing them out daily...thats the beauty of the industry..one does this, another does that and everyone wins in one way or another.
The little 4 and 6 cylinder engines out there today..screamers in the pure sense of the word...some are so-so engines and the so-so will be here long after the screamers are gone..the screamers are 90% plus designed interferrence fit..not a good combo when the rubber band breaks...there are a few that are plenty powerful and non-interferrence fit..this is the trade off. RMA Reliability, maintaibilty and availability...that is the true test of a machine.