I have a '71 351w with a lunati bootlegger cam, Holley 80458 4160 600cfm carb, Stealth intake, MSD Igniton, headers, the usual bolt on stuff. Motors stock otherwise. I got the engine pretty well tuned up where it will idle very well and runs decent, doesn't load up. I'm having issues with the exhaust stinking and burning my eyes at idle.
I am tuning with vacuum gauge and I have an AFR gauge installed, just calibrated(in open air per innovate). I have my idle set to roughly 550-600rpm. Initial timing is 14*. The cam is pretty radical, making only 8-9psi of vacuum, so I changed from a 6.5 to a 4.5 power valve. I have glass sight glasses in my carburetor, so the fuel level is 1/4 of the way up as per Holley. Setting idle mixture to highest vacuum and then trying to tune with the AFR gauge keeping everything as even as possible. Engine will stall when idle screws are turned in any more than 1turn from bottom, they're about 2-2.5 turns out. It is reading between 12.5-14.1 at idle. I tried tuning it higher and lower. Still stinks to high heaven. I am aware that a lean condition can cause exhaust to smell as well as rich, but i am not sure which way to go. Reading the plugs, #1 is ok #5 looks a bit rich. I also tried adjusting the initial timing between 12-16* but didnt see much of a change. I definitely notice changes in engine performance while adjusting the idle mixture but I can not get rid of the gassy haze coming out of the tail pipes, Im not sure if my wideband gauge is lieing to me or I have something else going on. Any input would be appreciated, thanks.
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