Does the engine need a complete rebuild? Stock intack and Q-Jet are your best carbs for the car unless you go high end new tech.
068 Cam is stock with a 400 HO. You have to look at adjusting your cam for pumped gas. Find a Pontiac engine builder. The guys can recommend someone close to you.
Need to plan what your intend to the car will be when your done. Street rod, Track racer, driver etc.
How much HP? CAM? tranny, Auto, Std? rear end gears??
Engine Test Stand Playlist: https://www.youtube.com/playlist?list=PLwoxyUwptUcdqEb-o2ArqyiUaHW0G_C88 restoring my 1968 Firebird 400 HO convertible (Firedawg) 1965 Pontiac Catalina Safari Wagon 389 TriPower (Catwagon) 1999 JD AWS LX Lawn tractor 17hp (my daily driver) 2006 Sequoia 2017 Murano (wife's car) 202? Electric car 203? 68 Firebird /w electric engine 2007 Bayliner 175 runabout /w 3.0L Mercuiser__________________________________________________________