if you have the coin to drop on it, a turbo will add a substantial amount of power, but expect fab work, and a LOT of tuning.
another stroker would be a good idea, poor man's 4.5l would be a good option (lookup Dino's stroker pg), but parts would be hard to come buy (not enough time). Hesco, Golen and Titan, are a few companies that make "bolt-in" strokers, but they can be pretty pricey.
chevy 350, a little more complex, transmission adapter will be needed, but engines are a dime a dozen and parts are as abundant as flies at a turd factory.
those are the two most common, but if you can dream it, its been done.
check out jeepstrokers.com if your interested in building/buying a stroker.