Quote Originally Posted by dbextreme View Post
You'd need more then an idle bump on an XP cam.... Gotta have shift points changed for the powerband or you might as well go with the S1X or VS...

And, yes in a perfect world having a tuner that knows that they are doing, an in car street tune is the best option.

What other mods are going to happen?? For an XP cam, don't you need stiffer springs in your heads or can you run stock?? I'd rather take the time to pull the motor to do the heads properly then keep it all in the car and work around everything. But that's my opinion.
A stock trans will be shifting by 6000+ rpm anyways. so it won't matter.

Some professional tuners will argue that they can't acheive the speeds required for testing high engine speeds long enough to ensure accurate data without a dyno.

Even on a mildly modded grand prix, you'll easily break legal limits tuning the thing even if you never get out of second gear.

What are you doing to do to the heads while having them out?

Port and weld the cracks? Might as well buy vendor heads at that point.