Ok I'm planning to eventually buy a short block add 9.8:1 pistons,after market heads that will be ported and polished then port matched to the intake and exhaust manifold gaskets, a 270 Grind Comp cam,Headers with 1 1/2" primaries true dual exhaust with a H or X pipe and a chip My question is if it's 160HP and 225Ft Lbs of torque stock what will all that get me???

 

Here's a group who did some modifications:

4.0L V-6 Tuning Tricks - Engine Performance - Ford Rangers - Ford Explorers - Sport Truck Magazine

Looks like they got a 20% (25hp) bump for all the work they did (replacing the heads, intake, and exhaust). They think a bigger cam would have provided greater increases, but I did not find an article describing that.