Has anyone experienced success with pods/non-stock airbox?

I'm just wondering if anyone here has had success with a non-stock air filter. I'm using this cognito motors airbox: https://cognitomoto.com/products/cb750-air-intake-box-sohc-and-dohc?variant=11585137601 on my 1980 CB750C and I've been having some trouble with it. I thought it would be better than just pods because it's an airbox but it's been problematic. I couldn't take the bike above 55 mph. I took it to a local carb shop too, but that didn't help at all either. I still can't go above 55 mph even after the mechanic worked on the carbs a little. The bike is still running way too lean.Has anyone here had similar experiences? Has anyone here been able to get good performance out of a bike with carbs? Any CB750 owners here able to get 100+mph and good acceleration on a bike with pods/non-stock airbox? via /r/CafeRacers https://www.reddit.com/r/CafeRacers/comments/8e80im/has_anyone_experienced_success_with_podsnonstock/?utm_source=ifttt