Hi I am trying to tune a holley 650 dp, which I recently bought used, with 2 oxygen sensors, one after each header collector. When I check wide open throttle the left sensor consistently reads about 1 AFR ratio leaner (13.4-13.8 mostly) than the right (12.3-12.6). At idle and part throttle (primaries only) the readings are even. I have tried spraying all the secondary passages with carb cleaner with no change. My Edelbrock carb gave even readings across the board. The engine is a 302 with ported heads, cam has 228 duration at 0.050. I spoke to holley tech support and the rep thought this was normal. Does this seem right? Any suggestions on other things to check or change? Thanks.