I think Rod Birleys car laps Brands Hatch Indy circuit in about the 50/51 second mark which is enough to be in front of many modified saloons such as Steve Weatherley,Ron Kiddell etc.
But if his RS went head to head with any of those awesome Historic Thundersaloons it might be a different story.
I wonder what the Zakspeed and Boss Fords are capable of on the Indy circuit.