Can you post a pic of the cam side-on, Peder? I believe the 5/1 is the std SF1 cam. My early SF1 (13768) came with an unmarked cam that I always suspected was a 4S (750S?) - it closely resembles a 5/C (74 SFC) with a similar broad profile (and very similar timing specs) - and the bike was a very willing revver, which seemed to confirm my suspicions.