Sorry to start with some bad news, but hyperpak are getting pretty rare, and very very expensive. If you have the money for it a hurricane manifold would not only be more cost effective, but most likely better performance. The idea of plenum intakes is makes perfect sense to me as most engine stuff is controlling flow and pressure of air into your chamber to maximize potential at a certain rpm. However, the hyperpak was designed for the 170, and without some other modifications mostly camshaft (this was part of the hyperpak combination in the day source: allpar.com) this will be a lot of money for little gain making your hate your slant six and trading it in for the more common 360
. Headers, are most likely a neccesity (don't quote me on that), but so would a heated course to your manifold to help with warm-up and streetablilty. Once again the only common headers are Clifford which you need to use the Search function or jump onto the "Other" section and read about them. Don't trust opinions outward, but with advisement.
I think money could be spent in other places with better results. In short, Erson group buy camshaft, ENGRBLDR's oversized valves, offy intakes, or super six would be less money and give you a more satisfying result. Yes the hyperpak is cool and I want one too, but to me and others it's simply not the performance item or coolness I want to pay for.
Wes