Flipping the upper lid will reduce the desired ram-effect of the OE designed air cleaner lid, as well as reduce the amount of air-flow.

The newer design aftermarket FLAT upper lids actually reduce air-flow by taking away the ram-effect.... but some say they look nicer... and you get to spend/waste money!

In other words, a contoured upper lid (matching a same contoured lower base) will always perform better than any air cleaner without the desired ram effect (up, over, down into the carb).

Mopar Mitch "Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers! Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!