Someone on this forum swapped in a 3.5 SOHC into their DOHC truck can't remember who though. those motors can be had cheap and low milage still. I think you loose 10 horse and gain 10 ftlbs of torque, That's the nearest drop in I got mine from an '03 or '04 with 44k miles for under $1500. Other swaps would require a full shop and money but with a swap you could get into the 300 horse range.