4.2 would be the best choice of those options, and to explain the extra power...displacement = power.
Now if you are to restricted on the intake side then you wont see nearly as mush power from stroking the motor. Also stroker kits are good for boost, stronger bottom end means more boost.
2002 v6 manual, SSM P&P Heads, Comp Cam from SSM, and some other stuff full list in profile.
214 RWHP, 215 RWTQ :tongue
"The trouble with our liberal friends is not that they're ignorant; it's just that they know so much that isn't so"