"The car behind the Scarab is definitely the Sadler Mk.V.  I’ve been in communication about it with Jack Boxstrom, the current owner.  Following are his comments on it:

"It is the Sadler I now own and race, however probably not with Peter Ryan at the wheel though -- it is either Dan Shaw or Grant Clark since Ryan had switched to a Comstock-Canada Lotus 19 by then."

Tom Schultz, Road America historian, however, is quite sure it is Peter Ryan driving, based on his notes."