Hi sapphire,
Well it depends. You are just going out and buying one completed or are you planning on building one? If you are buying a completed Cobra, then it depends on how much you would like to spend. You can by a duplicate of a real 427/SC if you have the means. If you want to build one follow the instructions below:
1. Ask around at Club Cobra "Who makes the best kit?" This will cause a flood of flame posts that will cause the server to have a stroke.
2. After deciding that you liked one users answers and thought he has pretty pictures of his motor, ask "Which motor should I use?" this will again cause the server to have a stroke as well as the administrator.
3. Finally go out on your own and research all of the various manufactures websites and posts here at Club Cobra. You will find that each manufacturer says "Were the best!" at which point you may decide to go back to Club Cobra and ask "Is this Company the best?" That may cause the server to smoke like an FE with a valve cover leak.
4. After deciding on the Company to go with place your order and send off your money. Then wait....................and wait................and wait....................... Then get a call from the manufacturer saying that it may take a little longer that expected. Go to Club Cobra and complain. Others may join the weeping.
5. While waiting for your kit, make a budget for the parts you will need. Then double it..........and say "Wouldn't it be nice to have....." add 10%. Continue to add 10% for every month you are building. If you are married and your wife asks you how much it will cost, double it again.
6. Find someone to build you a good engine. Ask on Club Cobra "Who builds the best engines". You know what happens next.
7. Your kit arrives and you start your build

. Say good-bye to the wife and kids and head for the garage. Oh, I forgot to mention...add 30% more for all of the extra tools that you now need. Oh, and 30% more for the out of garage expenses like welding, powder coating and the like. Buy beer and stand in front of the giant pile of parts and say...... "I don't think I can do this".
8. Sell the kit for a loss and buy a completed Cobra like you first intended.
---Just kidding.
Let me know an approximate range you would like to spend and if you want to build or buy a completed car. It would also be helpful if you told us what you want to do with the car when you have it. Like racing or show car or Sunday driver.
Thanks,
Mike