The oval hole gets a rubber grommet with 4 holes in it that cushions the temperature line, choke cable, throttle cable and oil pressure line. the two smaller round holes above and below the oval are for bolts securing the tin that holds the grommet.
One vendor is Steele Rubber
https://www.steelerubber.com/firewal...met-60-0010-45 Other vendors sell it too, Steele just had a clearer photo than Chevs of the 40s....