First, Welcome to the forum! Now, trying to help you do this without being there is going to be difficult. I suggest that you go to the library or book store and look for books on tuning high performance vehicles and study a bit to give yourself a foundation of knowledge. Also find a local speed shop and ask about car clubs in your area. If you can get into a car club there will be people there, just like this "On-Line car Club" that can assist and help you learn. That same speed shop may be able to point you to a reliable mechanic. The ones that can be trusted are generally known to the local speed freaks and may even be one of them. And how about the seller as a resource? Or was he selling it because he did not know how to maintain it?

The car sounds like it is nicely set up and should be a real screamer. With a big block like that and 4.10 gears it will probably never see better than 10-12 mpg if that.

I'm not trying to put you off, but trouble shooting and making recommendations without specific information or being able to see, hear and smell is not something easily done.

Good luck and enjoy your project. Learning is all part of the fun

Pat