i converted my 94 silverado tbi over to carbed big block and it wasnt to bad..
first youll need a fuel pressure regulator to lower you 12-15 psi down to about 5-7 for the carb, and youll need a big cap hei dist with vacuum advance instead of your small cap dist with the igniton module,,
id recommend you neatly put aside all your wires and connectors from the original tbi incase you decide to go back to stock,im glad i did for selling reasons. and of course the intake and carb,recommend no bigger then a
600cfm unless you have internal motor mods done...also beware of the emission laws by converting over too they gave me a hard time..i havent seen any books on how to do this just trial and error for me..good luck