The best entry level EFI setup is the Holley Sniper. It isn't really a bolt on kit since you have to upgrade the fuel system, change some wiring and modify the ignition system. A complete Sniper install is more than most "backyard" guys can handle but it doesn't really need professional install, it just needs someone who has plenty of tools and plenty of knowledge.

I have a bunch of Sniper videos on my youtube channel.
https://www.youtube.com/channel/UCoSY4bQ7I23XK834NLVTC9w