[bigred90gt]

86 to 88 cars are speed density except california cars. California went to mass air in 88. In the air tube between the filter and the throttle body, there is no mass air sensor on the speed density motors. They are harder to tune as you mod them because there is no meter to tell the computer how much air you are pulling in so it can adjust your fuel and timing curves. On mass air cars (89 and up except cali cars which was 88 and up), the mass air flow sensor tells the computer this info and the computer adjust the fuel and timing accordingly. Someone correct me if I'm wrong on anything.