More hp

Change the rear axle to one out of a 2500. To get 100 hp look for a super/turbo charger kit.

F_O_R is, as usual, correct. You can use the rear end out of a 2500 and be just fine well up into the high HP range. However, the tougher...and more expensive....part is adding 100HP. That is no easy feat and will DEFINITELY require forced induction. If anyone comes in here and says "Just slap a huge shot of nitrous on it", don't. Unless, of course, you have the cash to replace the motor. 100HP means you're probably looking at an intercooled Vortec supercharger kit. How is your budget for this? With the supercharger, supporting mods (fuel injectors, fuel pump, belts, all the little bells and whistles required) and a good dyno tune you're looking at spending around $10k, no joke and that's a minimum. To get the most out of the blower, you'll need to get long tube headers, an aftermarket intake, and likely new gears as I don't know your ratio but you'll want 3.73's at a minimum. Budget $15k and you should be good. Just keep in mind....for $15k, you can get a car that can haul butt and drive that when you want while still having your truck as a daily driver. Car examples that can be had under $15k include: 1998 - 2002 Camaro Z28 and SS models, 1999 and 2001 SVT Cobra models, some 1998 - 2004 Corvettes, 1998 - 2002 Trans Am WS6 cars.....just depends what you want. Just throwing some options out there.