Be afraid, be very afraid! You are over your head and in danger of consuming large amounts of time, money, and garage space; and most of all, having a new hobby. If you tell us the vehicle identification number we can tell you if the car is special in any way. Can you take pictures and post them? What type of experience does your friend have relevant to this Mustang and is he willing to make a long term commitment to helping you with this sort of project?