I had a 79 Mustang Ghia with a 3 speed manual with overdrive, I ran it like a 4 speed. The performance exhaust tone was only available on a 302 with a stick or a turbo. My 83 GT convertible was 302 with a 4 speed. 85 was the first year for the Mustang GT to come with stainless steel headers. My 85 SVO had the option delete package and dealer installed roll bar. When the SVO was introduced in 84, there was a switch on the console a advance the smart and adjusted the engine when switched on for premium fuel. This was the only year to have a manual switch, later years the computer made the adjustment.