matsarge wrote in part, "... guess at 5%. At 5% that would be an 13HP increase for a 330 from 258 to 271. Based on the feel of the car now, I would take a 2-3% gain as reasonable. That would be a jump in HP from 258 to 263-266. Only a dyno knows for sure."
For the sake of discussion let's assume that by removing the charcoal filter which is in the intake for a reason, the engine did in fact produce an additional 13 bhp with no loss in driveability and no emissions penalty. In this case, how many of us could feel the 13 bhp difference in a street vehicle of this weight? I know that I could not!