If you are going with a shortie style header why mess with the center dump style on a stock bodied car? They are designed for a street rod application although I have seen a set on a pick-up truck, 440 engine, that needed just slight notching of the upper frame rail to work. Hedman makes an Elite series header that is routed much better and actually works well on a milder engine combination.
The steering coupler that was shown, from what the original manufacturer said, is no longer in production and is currently not available.