What is the best flowing factory cast headers for injected motors, and what hugs the block more?? I have a 304 I have put into my hilux, and rather than butcher and modify a really nice near new set of pacies I have here, i reckon I could suffice with factory headers and a decent flowing exhaust. What are peoples thoughts, are they all pretty much the same or are there some flow differences?

Instead of using GM headers I would get another set of cheapy extractors and get an exhaust shop to cut and re weld them.

VN-VP are not cast. VR-VS are the same as each other, and are the narrowest. VT are wider, i have no idea what any of them flow.