These are very nice pictures! Your internet surfing moves are the ballet of a free-rider.
However
As I said in the "Crusher" thread, there is a record of Sharp finishing second in the CP race at Summit Point, West Virginia on April 12,1970. And I provided the link to the website (which is a fascinating website collection of historic racing photos). Sharp's entries in that archive list SCCA National races. I wonder if Cumberland was a Regional? In these pictures, the car has no front spook - interesting. I'm surprised that there is no SCCA decal. Back then, there wasn't much advertising on cars. Everyone in the SCCA had pretty plain cars. The cars you are looking at from Sharp and Group 44 were cutting edge SCCA racers in car preparation and graphics. What a great photo of the 240Z squat with the inside front wheel up in the air! Lovely suspension mods, Bob.
Now compare Sharp's record in his 240Z to John Morton's http://www.racingsportscars.com/driver/archive/John-Morton-USA.html
Morton / BRE was racing a Datsun 2000 in C Production registered as a 240Z on April 26, 1970 at VIR. It doesn't appear as though Morton / BRE campaigned their 240Z until September when Morton won in Ontario on the 20th and Phoenix on the 27th.
What I get from this is the well worn rag about how Bob Sharp got the "crushed" show car quite early and well before Peter Brock got his. Yea, yea.