Okay, for cheap power here's an EASY recipie.
5.3L gen III engine
LS1 or LS6 intake
LS6 valve spring swap
small cam regrind
mill your heads
tune and possibly injectors
even with stock manifolds you're well past your HP goal, probably spending between $1000-$1500 total, and will have a more durable engine with better street manners than if you built that 283.
Yes its that freaken simple and cheap.