I finally got my carbs set on 72 and it runs great. The only problem I have is a high "relatively" rpm drop off which occurrs around 4200. When I remove the air filter the car pulls hard, up to red line. Does anyone know how to modify the original air filter assembly to make it less restrictive or should I go with some sort of after market filters. If you guys think I should go after amrket, please advise who makes the best and how much they cost. By the way, the filter is new and the air selctor is set to the summer mode. When I swithched it to summer, I was able to get another 300 rpms. Thanks iin advance for your input.