Whoo-hoo... Got the answer from Paul (the Technician).

He called Mustang Dynos before I came and said that the problem was the dyno was 'set' in 2-wheel mode, with the rollers connected by the belt.

With that extra mass and being in 2-wheel mode, the calculations are incorrect.

So, we threw the SRT6 back up on the dyno and lo-and-behold 249 HP @ 5,750 RPM and 252 FP Torque @ 4,500 RPM. The curves look almost identical to the ones I posted previously. I'll scan it in later tonight.

The only thing preventing more HP out of it is it forces the transmission to shift... I suspect a manual will have a better time of it.

Also, we ran this test in 3rd gear... he was reluctant to do 4th because of the RPM of the rollers becomes VERY high.

I'll take this as a good baseline and probably the car was de-tuned some for California... at least compared to the 275 HP on the SRT6 dyno from the UK.

Next stop... Pulley set and Upsolute Upgrade... I'll be doing dyno runs after each mod.

May do the Upsolute first as it's the least expensive of the two.

EDIT: Oh yeah, Paul didn't let me pay him this time because the dyno wasn't set right the first time.