My Promaxx jet plates work great. I did have issues with new needle and seats. They seemed to pull out of the threaded portion of the fuel bowls. These were Holley parts, not made in China. I had to have all three floats bushed with a brass insert. My biggest problem with my six pack was keeping the floats set correctly. If they are not, nothing else really matters. Are your floats set correctly? Next biggest issue is the air fuel mix. Once these two are dialed in, you can fine-tune your jet selection or drill the plates. A buddy of mine drilled his stock metering plates and tapped them to insert Holley jets. It works good for him. Cheam man's Promaxx plates.