I have a 2Bennett chip in my 1986 5ktqcs. If any one is concerned about passing a smog test with this chip, don't worry. IDLE Limit Actual HC ppm 220 59 CO % 1.20 0.01 2500 HC ppm 220 46 CO % 1.20 0.00 I am also running Nology spark plug wires, Amsoil A/F, Amsoil oil and 3" high flow cat and exhaust. Peace Grant