i want some nice 200cc heads for my 357, im thinking either Sportsman II or Dart Iron eagles. i see the flow #'s on the sportsman II's are better but but i dont know how much they are yet. anyway, i want to match the runner size on the heads to the intake manifold gasket. is doing it yourself advisable? i take it all you need to do is match the intake gasket on the head and get a magic marker to outline the areas that need to be shaved off. a simple grinding tool? also, i know you're not suppose to go farther than about a half an inch down. i have some junk heads to test on, but i was wondering if this is better left to a shop. thanks