225 /6's created equal?
The Super 6 with the Carter BBD also came with a 2¼ exhaust system. I think that the exhaust manifold outlet was enlarged to accomodate the larger pipe.
There were some earlier Super 6s, but I think the only thing that made them super was the fact that they were bigger and more powerful than the standard 170 CID.
The Hyper Pak was a unique animal and extremely rare. Besides the 4 barrel on the L-O-N-G ram manifold, the engine also had a 10.5:1 compression ratio. The carburetor was mounted sideways with the primaries towards the engine. The cam was a mechanical cam that on the 170 had a duration of 276-268-44º and a lift of .430". (Sorry no figures for a 225 Hyper Pak.)
According to Mopar 6 book, the 71-77 mechanical camshafts are the best regular production pieces available in general circulation.
Although not real prominent, there is an active aftermarket of products available for the /6. Attitude at SlantSix.Org isn't as laid back as here, but there is a wealth of expertise and information available on the Leaning Tower of Power.