Silver9k

give us lots more info...list everything related to your turbo and your mods...

and saying you have a T3/T4 is almost as much information as saying you have a turbo on your car...there are many different trims and variations of T3/T4 turbos...

s2kboost

im not to sure of the trim and my first run with was my best of them was a perfect rising ark smooth as hell no dips or anything, i think if i get a greddy emanage, fix my turbo which has lots of turbo play and get rid of my high flow cat should bring me close to 300. after my first run the horse power went down alitle and i took some fuel out and wasnt as good.

revhi

I find it wierd that your torque is so high, but hp low. I wish I had your torque numbers.

Sideways

Mustangs read lower than the other dynos. 260 hp on a Mustang dyno is about 275-280 hp on a Dyno-Jet and 290-300hp on a Dyno-Pak. That's about what is expected.

s2kboost

i put down 260 on both a mustang and a dyno jet

SpoonS

DAMN THAT SUX something has to be wrong i would have a really good tuner/installer in your area have a look at your vehicle
HANG in there should be resolved.