Considering he has an AOD, I don't think the short throw shifter, quardrent, or firewall adjuster will help him much.
I would definatly go with 4.10s. Get a SHIFT KIT for that car. A shift kit will not only improve performance, but it will also extend the life of the trans because it increases line pressure which doesn't let the clutchs slip, the number one thing the goes bad in an AOD. Then I would put under drive pulleys. They are the best bang for the buck part. Save header, and throttle body and MAF until you get more balls. They won't help much on a stock motor. Do an oil change, and do a basic tune up... Good wires, good plugs, good cap and rotor. A torque converter will also wake up the AOD, get a 2000-2500 RPM stall. Hope this helps.
Nick