What will be critical is knowing what's damaged and what's reusable on your old engine (metal in the oil isn't a good sign) - if you only need a bottom end and can reuse your heads, I think that would make it a much simpler swap than trying to get the SOHC heads and intake to work in your truck. It's kind of getting into uncharted territory as far as I know, but I think a 3.8 block & 3.5 DOHC heads could make a solid 250hp engine.