Jason,
A lot depends on your budget and your timeline. You need to realistically determine how much you're willing to spend for the entire project.
Your first step will be to narrow down the list of manufacturers by researching this site, checking out their websites, ordering literature, attending car shows, and visiting facilities. Once you have it narrowed down to about 2 or 3 manufacturers, then you'll wanna start talking to owners directly.
I started that process about 11 years ago. Most of that time was spent going to college and saving money. Weather you buy the engine or car first isn't really that important. A lot also depends on whether you plan to build the engine yourself. I chose to use a reputible engine builder and I'm very happy with that decision.
As xlr8or indicates, searching this site is a very important step in your research. Don't skimp on the research. You're talking about a 40- or 50-thousand dollar car here. Hope this helps.
Keith
