I start by saying that I am not an expert on these or any of the soc 4 bikes I am educating myself as I go on my 78k I do know what a sandcast part is as one of my early jobs was making sand moulds for tractor parts.what I have found in with parts that came with a 78 parts bike that I got last year are non finned oil filter housing sandcast.1 set early ko sidecovers and what I think is an early swingarm it has what I think are the no 8 bolts and a different spacing for mounting chain guard as it looks like someone had to elongate the rear hole on a later metal chain guard as seen on later pre 77 bikes. I am not a sandcast guy or hoarder so these parts will hopefully find their way to a bike that needs them.I would like any help in identifying the swingarm if anyone can please. thanks bill