i got a K&N intake system and straight piped into a flowmaster exhaust it gave me some notice able power gain and a good sound as well though i think a chip or PCM would help a lot more. I have a 98 blazer LT 4x4, i would love to rebuild the engine and put a cam in it.

 

For my 4.3 mods I have bored some 1.5" holes into the bottom of my stock air box and replaced the filter with a K&N. The muffler was replaced with a flowmaster 50 series. I have a march power & amp series underdrive pulley kit, and I have replaced the engine driven fan with an electric fan from an olds aurora. Along with keeping it well tuned up I replaced the transmission servos with corvette servos for a slightly firmer 1-2 shift.
From all of these, it revs faster, gets better mileage, and is more responsive at all speeds.
I would like a PCM tune, but don't feel like sinking that much more money into the current engine with 154k.
I am planning a 6.0L swap in the near future.

 

how can i mod my stock air box i have a k&n air filter allready lol

 

Its called swiss-ing your air box. Just drill a bunch of holes on the front to let more air in. Or...if you want to have a cleaner mod, install a deckplate.


They run ~$10-20 at a boating supply store, or you can order them online for cheap. This way you have a nice clean lip, and if you were to go offroading ever, you can always seal it back up.