The HP Package was only “officially” offered in 1964 and 1965 on D100 and D200 LWB trucks. The Custom Sports Special trim package was offered from 1964 thru 1967 and could be had on D or W 100, 200 Sweptline, Utiline or chassis cab in LWB or SWB trucks.
Dodge management only authorized 50 trucks could be built with the 426 Street Wedge High Performance Package — according to former Dodge truck engineer Bruce Thomas of the Walter P. Chrysler Museum, who said that far fewer than 50 examples were actually produced. Currently the registry recognizes 31 trucks with these packages or combinations of them.
For a great story about them, and a family restoration: http://www.cssregistry.com/css/stevebell.html