For the drag strip a lower ratio gearbox would help a lot (think Nova SR!). Cams, air intake, sports exhaust are worth doing.
Nos would also be an easy mod and really will help bring your drag time down.
For more money you can look at getting the head ported and polished and even rebore to increase the compression ratio and capacity! You will need to strengthen the bottom of the engine to help.
Put the car on a diet, reduce weight as much as possible and how was the traction. A Wheelspin can lose valuable time so get some wider wheel and better tyres.
