I added a second metering block kit (I believe its a gasket, fuel lines, power valve, jets, longer screws and the metering plate. I wanted better adjustment procedures out of it. I think I put a power valve block off in the secondary circuit. Its been a long while. My biggest concern for the slant and the 390 was the bog...I fiddled around with the primary cam, accelerator pump excessively...never could get rid of it...Start with stock jets and move up from there.