SELECT "Average Speed (mph)" FROM table_2078 WHERE "Team" = 'Jon Thorne'
What is Jon Thorne's average speed?
CREATE TABLE table_2078 (
    "Year" real,
    "Date" text,
    "Driver" text,
    "Team" text,
    "Manufacturer" text,
    "Laps" text,
    "Miles (km)" text,
    "Race Time" text,
    "Average Speed (mph)" text,
    "Report" text
)