I believe the "tractor" sound was an old Kodak projector, probably 8 or 16mm film from that era. Great cars all. Can you believe the way the crowds were wandering along the motorway and just standing on the walls a few steps away from these cars on the corners. To drive in that race you had to be very aware of what your car was doing as well as trying to drive all out to win.
G
i found this off of wikipedia:
"Due to the long track, drivers practised in the week before the race in public traffic, often with their race cars fitted with license plates."
