Gus I'm running an Allstar drop base air cleaner (4150) on my Dart. The guys that dynoed my engine do a lot of dirt track stuff and said that the Allstar base and lid along with the Wix racing filter Dom mentioned made more power on the dyno than anything they had tested.

Before anyone says anything, yes I know and so do they that dyno's aren't in an actual operating environment so take for what it's worth.