Steve--Regarding my 75 too rich 450slc. Using your advise and a gas analyser, My car passed the California Smog test with Flying colors. Of coarse I promply went home and richend the mixture up. Any Advise on what a good idle and off idle fuel mixture would be.I have sinced been warned that the afterburners run almost 300 degrees hotter when set to Calif. emission specs. MANY THANKS JOHN MILHOUS.