According to the VRG newsletter at :
http://www.vrgonline.org/newsletters/2005/0805-Vol2.4.pdfI found refences to "Phil Roettjer in his Lotus 6". You can read the name of the driver on the side (in the picture) and it looks like "Phil R----" to me, so I suppose this is the same preson.
I do not know Phil, but his car is lovely and it ran well all three days in NH. I never looked at the engine. I guess it could be an Anglia flathead, 1500 Ford OHV or maybe 948 Austin. I know they put all sorts of things in these cars.
This is a similar car at Watkins Glen (I took this last year)

By the way, here is a picture of a different Lotus (maybe also a 6?) I took at Lime Rock a few years ago. When you stood over it, the engine was very noticably offset (to the left) for driver footwell room.
