Jeff and the rest of you are correct in that there are so few cars to choose from. Finding a good one that is fairly priced is like finding a needle in the haystack. Any 45 year old car needs something, even if it has been restored. If you add up what needs to be done on a car that you are considering buying, as a retail repair value from a reputable repair shop, the costs are staggering.
A complete 1969 CJ mustang that needs restoring costs 18-25K. The same car that has been restored at some point where it is a number 2 condition car costs 52K to 75K. The harsh reality is that it is far cheaper to buy an all around nice car as opposed to restoring it, unless it is a hobby and you have unlimited funds. Reproduction parts are for the most part garbage. OEM parts are insanely expensive, if you can find what you need.
Ford FE engines are much more trouble than your garden variety 302, 351. Part of the reason is that the engine has been rebuilt and Ford FE experts may not have done the work, so you never know what you get. The other reason is that a guy that bought a big block 45 years ago had one thing in mind, to go fast and hard against the competition. I can't imagine an original FE engine in existence that has been unmolested and is still running good, although there must be a few in some collection somewhere. I have seen small blocks that are original and still run beautifully. I have a 289 now and sold a 6 cylinder that ran fantastic.
Collecting and maintaining muscle cars is expensive and time consuming, one must have the burning desire and a strong stomach to enjoy ownership. It can turn into a disappointing experience in a hurry if you are not realistic in your expectations.