well, i own a '97 ram short box w/sport pkg that has the 5.9L (360) F.I. horsepower rating is 235 stock. pretty poor for a V-8 huh. so i pulled the 360 and installed a 440 magnum that produces close...
This is a really vauge question. You need to present alot more info to determine the HP. Things like type of pistons, heads, carb and intake can make a huge difference. So my guess on the HP output...