if you want a proven durable setup that you don't have to worry about, take the original engine out and set it in the corner of the garage, and put in a newer block with a factory roller cam and one piece rear crank seal. you can get rebuildable cores fairly cheap, and the actual engine build doesn't really cost any more than an older 350.
order the HOT cam kit from GMPP- part number 12480002 from any dealer and comes with the cam, springs, retainers, 1.6 Crane built GMPP roller rocker arms, and a bunch of other parts- and put a set of Vortecs or Dart Iron Eagles on it with a performer RPM intake, and you will have a smooth, reliable 400 or so horse engine that will get mid teens to low 20's in the fuel economy department (depending on gears and driving habits, of course)and knock down high 12's all day long at the track, and it will look pretty stock if you use all the stock brackets and paint the intake to match the engine.
if you really are willing to spend the coin for the "best" valvetrain parts, then you should consider that you might have as much into the whole engine as you would for all the "best" valvetrain parts for your current engine, and 100,000 mile reliability is a given..
you don't plan sincerity.
you have to make it up on the spot.
wanna hear about 20 years ago when i was too smart to know any better?