[SST159]

I am curious as well.
I have been experienceing a similar problem ever since I changed my hood scoop last year on my door car. The old scoop I had sealed off with a pan and foam to the top of the scoop. The new scoop is much larger which I have not sealed off and lost at least 2 mph and have gained an occasional engine miss during the pass. EGT is showing lower than normal as well indicating a richer condition.
I have tried it with the pan (Pan only no seal) and without and see no difference other than the motor wants to stall when I click neutral with the pan on. I am suspicous that there is air turbulance causing the MPH loss and the stalling deal on top end. (unless ironically other problems have cropped up that I am not seeing ie electrical or motor)
I am going to try my next race to seal off the scoop with the pan a huge piece of foam and see if that makes a difference. Any suggestions or comments would be appreciated.
BTW the new scoop is open in the back and the old one was closed.