A date code engine will be a harder find and take some time to search for but see what you can find. I've seen people (and still do) search for years for correct dated parts. And a running engine is by far the best find. Now as you get into the books you will notice some FE/FT blocks share the same casting numbers. This is where you will need to check the bore and crank stroke etc....of the engine to verify what it is. No biggie but it can get a little confusing. So as good as a running engine is to find it's also good to know what's inside as well. I've had some real cobbled junk over the years. Mismatched rods, pushrods even pistons! found in running engines. But that is easy enough to correct with the right parts. I would not get too hung up on the date code thing. Maybe you can find a nice running engine to use then look for a correct date code engine as time and money allow. At least you can drive and enjoy the car as you decide which to pursue. That is unless a correct date code engine comes your way.....then grab it! G.