I have a stock 80 5.0 will the heads in this kit work with stock headers until I change them to BBK shorties? Also, would it be smart to get a 70mm throttle body and EGR spacer with 76mm Mass Air Meter at the same time with 24lb injectors?
You can run the factory headers for the time being, just keep in mind they are restrictive. The intake manifold is capable of utilizing a 75mm throttle body, but a 70mm will also work just fine. The mass air and injectors you mentioned would be perfect for this combo.