SELECT COUNT("Race Time") FROM table_73423 WHERE "Driver" = 'Cale Yarborough' AND "Average Speed (mph)" = '88.924'
How many races did Cale Yarborough win at an average speed of 88.924 mph?
CREATE TABLE table_73423 (
    "Year" real,
    "Date" text,
    "Driver" text,
    "Team" text,
    "Manufacturer" text,
    "Laps" text,
    "Miles (km)" text,
    "Race Time" text,
    "Average Speed (mph)" text,
    "Report" text
)