How about a 1.6 based 3.0?? I talked with a local machine shop lately about upsizing dramatically. It seems as though it can be done, a lot of custom machining and custom head gasket and pistons. The cost is pretty high, though. I was told about $3,000 for the completed long block! But you don't have to adapt another motor or trans into your truck. The power is supposed to be about 220hp with like 230-250lb-ft of torque! Pretty cool, huh?
Not really a good idea, the largest 4 cylinder
engine was a 2.6 Mitsubishi, and had to have
ballance shafts (rotating weights) to get it to
run smooth and not tear it's self up
If you were to go 10mm on both bore and stroke
you would get 2270cc and thats pushing things,
you would be looking at new pressed in cylinder
sleeves, and a custom forged crank (stock cranks
are hollow

)
Realisticly a 1.8 or so is the limit in the 1.6 block
and that would be a little pricey, but affordable
Wild