skewing the dyno??

crackedback said

One of my favorite dyno claims was changing from a set of 1 5/8 hookers to A body tti 1 5/8-1 3/4 steps headers and a pick up of 45hp was observed.
Were there bananas stuffed in the hooker collectors?
Might want to hook up that 8th spark plug wire when running the hookers.

It's easy to mess with correction factors, whether software or mechanically.

Click to expand...

That's funny because when I dyno'd my engine I gained 26 hp from a header swap, 2 inch to 2 inch / 2-1/8 step headers ....then I wanted to run the exhaust as it would be in the car, so we removed the dyno exhaust....it picked up another 25 hp.... So, that's a 51 HP pick up total.
There was no messing with anything except for removing a restriction.
I'll be putting this engine back on the Dyno soon if you need proof.