This is a lightly used Sifton Cam, model 104. It was called the “Silencer” I believe this was manufactured in California, between the death of Tom Sifton and the purchase of his company by VTwin Mfg. But I am no expert. The second picture shows cam specs for a 104 Silencer. This is for the cone motor and has the groove (1977up) the same as Harley factory cams. So 1977-78 up thru 1984. Solid lifter conversion most likely. Besides the Sifton name on the gear, it is marked 104 on the first lobe , and AQ on the second. Comes with spacer shim.