There was no way my stepped TTIs were fitting on the dyno. I'd rather dyno with dyno headers than be finding things out the hard way once the car is screwed back together. I agree with getting it as close as you can but saying it's worthless to dyno unless everything is installed 100% as run in the car is foolish. Finding leaks and ensuring valvetrain stability are high on my list.
I have had a set of BBM TTI's on my dyno, required me to trim a mounting plate on the drivers side. Then again, your headers may be different.
Joe
