If you are running the Auto Trans, you can't.
My previous truck was a '95 488ci w/5sp. I put a set of Doug Thorley LT's, Mopar Performance Cam and Crane Springs. Ported/Polished Heads and Intake.
Crane Rep. asked about my Trans, and stated that Auto would not hold up (he used to work at Mopar Performance).
My manual was just fine, and that truck would eat mousestangs, could also pull 8k lbs trailer through the Smokey's in high gear.
50 hp is a lot, but you can pick up some torque in the range you need it I bet. You share a transmission with the Cummins, it can be built to handle whatever you can send it's way, not an issue. A tighter/better torque converter will help a bit. I have one built by Hughes Transmission in Phoenix, not yet installed, billet cover, solid and the price rocks. I picked up a little bit with a throttle body mod, no dyno proof, just a feel. I posted this: https://www.ramforumz.com/showthread.php?t=241889 Polishing the inside of the intake is a fairy tale. Cut it apart and reweld it maybe. Port and polish the heads, why? The ports are huge, and look pretty well designed, until you start making some serious power, they are not the cork. Manley makes a nice set of stainless valves for the Viper that will fit. I had them backcut and a fresh 3 angle valve job, when when the heads were built. I had to change out the valves springs because of a difference in installed height however. Cam and compression are what you need I'm betting. My machine shop used Herbert Cams in Southern California for a regrind of one of the stock cores I have, sweet price. I also milled the heads for about 9.5:1. You'll have to measure and fit a new set of pushrods after both of these. It was also necessary to cut the top of the valve guides for clearance. Muscle car basics, cam, compression, exhaust. Your computer is programmable, my '95 is not. I'm sure some help is worthwhile there. Gears, depends on where you start. I run 3.54s with a 33.5 in tire. Right now, not interested in a change to a lower gear in the interests of RPM and fuel mileage. The truck pulls plenty strong. I'd consider 3.73s, but that is a 600 USD+ investment. Good luck, Mike.
Low restriction air intake, 1.7:1 rockers (add new, better springs as well), low restriction exhaust. Anything more and you'll need to get into the block for cam change, etc, along with head work. Those 3 areas will get you close, as well as broadening the power curve, which is more important than peak power. Also, if you did change the torque converter, I'd go with a looser, or higher stall speed (along with an external transmission cooler if you don't already have it).