I can guarantee that Project 5 works in Windows 7 64, but I'm not sure about 8. I know that doesn't answer your question. I have a hunch it will work for you, though. If no one else responds, give it a try and let us know how it works out.
When I installed it in Windows 7, I installed version 2 from the CD, making sure to include all of the options. I then installed the 2.5 update, and the update to that (2.5.1 or something like that). Works great, and I still use it a lot.
Finally, even Kinetic 2 works for me in Windows 7 64. But, it did not work until I did a clean reinstall of Windows 7 64 a couple of weeks ago. The first thing I did after getting win7 up and running was to install both P5 and Kinetic, and they both worked right off the bat. I did not get the "Directx 9.0 not present" error when trying to install P5, like I did when I tried installing it after I'd had Win7 running on the machine for a year.
The only thing that refuses to work is the old version of Pyro (the version that came out over ten years ago).