Are you going to try and go rounds or are you just going to play with the car? If you want to go rounds then you'll need to put a bunch of stuff into the car to make it reliable and consistent.

You need about 1 hp for 5 pounds to run 10.00 so that should be your goal. If the car will weigh 3000 lbs with you in it then you'll need 600 hp. If 10.0 is your goal then you can figure out how much power based on the weight. Once you know how quick you'll go you can figure out the MPH at the stripe. If you are running 10.0 then you'll most likely be around 135 mph. Once you know the MPH you can figure out engine speed and rear gear and tire size. As you work your way thru the numbers the car design starts to come into focus.

It shouldn't be very difficult to build a 3000 lb Duster on a budget. If you are going to run low 10's then you only need a 5 point roll bar so you can skip the full cage setup. If the car is 3000 lbs with decent weight distribution you won't need killer tires out back. The big tires add a lot of cost for body work since the fenders need to be reworked. Are you doing the body work and chassis work yourself or hiring it out? If you are hiring it out then you'll want to reduce the amount of work needed.

Not much reason to worry about the engine since almost any combination of good heads and decent compression will net 600 hp but you do need to figure out all of the little stuff like alternator, water pump, radiator, etc. If you have a generator then you can skip the alternator but that can be a hassle. If you need to run an alternator then the motor plate becomes a hassle. So there are lots of little decisions like that which you need to think over. It really just gets down to what you want the car to do. When you take it to the track do you want to hang out with friends and make a pass or two or do you want to spend all day in the lanes trying to win the race? If you want to win races then the car needs to be set up to help you go rounds.