It depends on what boost level you run, other modifications and trans type. Superchargers dont have a set number of power they add, they go by a percentage gain. A vortech with no cooler has around 45% or so with a cooler mabye another 10% or so. For example HorsePower T.V. put a Vortech on a stock 96 ( Exhaust, TB, and a Catted Xpipe only mods) it was a five speed and dynoed 204 before the blower and 286 after the blower with no cooler and 8 pounds of boost. That was about a 40% improvement over the orginal dyno without the blower. In a later show they added a Power cooler and got 301 for another 15hp. I dont think they said any numbers on torque. With a Pro charger the giains are higher by the percentage of hp gained, 55 to 70%. I think their blowers are more efficent than the vortech also. I ordered Pro Chargers info packet a while back and it is full of info on power gains and et gains. Give them a call 913.338.2886
98blackmagic is right about percentages instead of hard numbers. Also know that to get the most out of the S/C you'll need additional mods such as mid pipe, catback, MAF, and preferably an intercooler for safety as well as more power.
For comparison, my 2000 GT Auto dynoe'd ~380 rwhp before the Comp cams were added (same as 400 rwhp on a manual). With equivalent mods on a 98 GT I would expect maybe 325 rwhp (342 on a manual). I only mention this so that you don't expect the same power levels you see on equivalant blown 99-04 GT setups. This is due to (stock) 98 engines having a more restricted airflow.
98blackmagic is right about percentages instead of hard numbers. Also know that to get the most out of the S/C you'll need additional mods such as mid pipe, catback, MAF, and preferably an intercooler for safety as well as more power.
For comparison, my 2000 GT Auto dynoe'd ~380 rwhp before the Comp cams were added (same as 400 rwhp on a manual). With equivalent mods on a 98 GT I would expect maybe 325 rwhp (342 on a manual). I only mention this so that you don't expect the same power levels you see on equivalant blown 99-04 GT setups. This is due to (stock) 98 engines having a more restricted airflow.
True, depending on how your motor is doing now in your 98 should play a big part in how you go, if if has high milage, burns oil, or just runs poorly you may want to think about getting a motor out of a wrecked car or from one of the stang part shops (Mustang Part Specialties) for example, getting a PI motor would be a big plus too . This would give you the new PI heads, intake, cams that the newer cars have and a newer bottom end that would most likely have less miles than your 98 does now. Just something to run thru your head before you spend money on a blower , the more you plan ahead the better you will be in the long run . Best of luck to you and your 98