Possible combinations of 8 digits, 6 upper case letters, 2 distinct numbers
Close.

It's $26^6 \times 90 \times 8 \times 7 / 2$; the $/2$ is there because having the digits appear in locations 1 and 3 is exactly the same as having the digits appear in locations 3 and 1, and hence there are only 45, not 90 distinct locations where the digits may appear.