There's been a lot of good replies to your question of how to build your car. I wanted to share some hindsight from a number of projects I've been involved with over the years. In the end you'll decide if any of this is useful or not.
1. One of the toughest decisions you'll be faced with is do you want a street car that can tracked or a track car that's street legal. Those may sound like the same thing but they are from from it. The first involves adding performance using the Z chassis for the most part similar to the Green Hornet mentioned above. The latter is much more like building a chassis and dropping the Z body onto it. This gets you more to a car like the Fairlady Z06 mentioned above. This also determines if you start with a solid chassis or you use one that's nothing more than the roof and doors.
2. Research, research, research. I'm not trying to be funny but you need to have the entire build plan figured out before you start. Then create a checklist and start crossing of items. This research and list will help you build a budget for the car. It may end up being a lot more expensive than you imagine (nothing wrong there) and you may never want an SO to see this spreadsheet. But if you've done your research and stick to your plan you won't but parts two or three times to get the right item. It will also keep you from having to figure certain things out along the way, which really adds up time wise. And lastly it will keep you from having scope creep. The latter can be a real killer of projects.
3. Determine/buy the drivetrain parts last. This is engine, transmission, wheels & tires, etc. If your project takes more than a year to build it's often possible better items will come along or prices in scrap yards will get better. The only time I'd say you can break this rule is if you have determined their is a specific drivetrain you're going to use and it's not going to get any cheaper and in fact may be harder to get later on down the road (L28ET for instance).
4. For the things you can't do find a good professional that can help you. While it's often tempting to use a buddies buddy or someone doing this from their home I've seen a lot of projects get stalled this way. This is generally around body and pain but could also be around having a roll cage built. For any vendors you plan to use take a look around to make sure they have a good track record.
I wish you luck and good fortune on building your car. In the end there's nothing better than something you built yourself, well at least to me.
Cary