How much gain from Powerdyne to Vortech S trim?

Did you have a tune with the old supercharger? With that 155 don't seem like that would be enough fuel.

must have meant 255

You're probably gonna want bigger injectors, and a 255 if that truely is 155. My buddy (bentley429) just finished his h/c/i s-trim car that used to have a powerdyne. He's running a 255 and 42s now and ran out of fuel just over 5k. They said he needs an inline as well. So you're definitely going to need more fuel. As far as the difference? First thing you have to do is have it dyno tuned, it's not even an option. Once it's dyno tuned you'll **** your pants, honestly. I believe his Powerdyne was seeing around 7-9 on the gauge, and the s-trim is making 10 at 5200 rpm. After putting the s-trim on his car, he was disappointed because it didn't feel much faster than the powerdyne. After the tune he gained 110 rwhp and there's still another 50 coming with more fuel. I bet you will see a lot more than 2 mph.