When I saw those numbers a few months ago I thought is sounded a little high... but then I remember what they posted AND WHAT THEY DIDNT POST.
I am sure that is a true number and very plausible... but think about this...
They did not state that peak power or peak torque went up, but that there was an increase... it could have been at any rpm for many different reasons.
They did not post the dyno graph to see the actual difference? Anyone who just posts numbers without a dyno graph is usually trying to deceive someone. Why would you take the time to dyno test, make a big fancy add with pictures, and then just state the numbers with no graph???
Before swapping did they verify the truck had good stock pipes? Or could they have been blown up pipes that were leaking really bad?
Here is an easy representation of "deceiving numbers"... I am not saying that is what they did... but why not post up the dyno graph and more info so we know they didn't.
You can the blue line has an increase of almost 150 ft/lbs of torque for the red dyno
You can see the black line had almost a 75hp increase for the red dyno
But the green line made more peak hp and peak torque...
The reasons the red line made "more power" is because it spooled up faster... by approximately 75rpms??? Thats it... you would not be able to tell the difference between these two setups on the street. Trust me... they were my dynos and my truck. This was just used to show how you can deceive people by just posting numbers.
IMPORTANT>>> I am no way saying that there is anything wrong with the sinister pipes... In fact... I have a set on the way right now