I am in the process of putting together a 69 Mustang, pro touring type build and looking for thoughts on how to modify the engine.  It’s a 428CJ with TKO 600, full TCI suspension, 3.89 gears, etc.  The CJ was built by Knieriem racing engines in Louisville but it’s close to stock, I have the build sheets.  The internals are all stock, the only mods are Comp 280H cam, upgraded rocker system and Performer RPM intake.   I have a set of Hooker Super Comp headers that I will run and plan to use an EFI instead of a carb and a good ignition system.  Plans are at a minimum to pull the heads, port match intake & exhaust, clean up the runners, etc. Thinking that should put me between 400 & 450 HP?  I am thinking that the cam is a little too mild for my setup.  I was hoping for 500 but don’t think I can get there without going to a Stroker kit or nitrous.  The car will be driven, not a garage queen.  All thoughts and recommendations are appreciated.