Lonesome is right. Chrislwg did the oil cooler mad. If I remember correctly he piggy backed the oil pump and fitted unions in the engine casings. He doesn’t log in very often but I will try and contact him.
I have been in the garage with my tape. On the CSR the distance from the cylinder head to the frame is 200mm maximum in a horizontal line. This decreases going upwards due to the frame tubes being at an angle and may be slightly different on a B frame.
I will try and get the oil pressure switch thread this weekend.
If still needed I think I have a spare exhaust cam.