cvfc1216

so i have my 1998 gmc yukon with the 5.7L 350 V8 vortec in it. over the years it has seriously lost power any ideas as to what to do to regain some if not all if not add some more power to it. as of now it is stock. (plugs, coil, cap&distributor, airintake ect...) nothing too complicated please. and dont say supercharger cuz i already know it would blow the pistons to hell.

oh i forgot there is a 1" throttle body spacer installed.

any ideas are appreciated.