The generator matrix

 1  0  1  1  1  1  1  1  1  0  1  1  1  1  1  1  1  1  2  2 2a 2a^2+2 2a  1 2a^2+2  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
 0  1  1  a 3a^2+2  0 2a^2+3  a 3a^2+2  1  2  2 2a 2a^2+3 2a^2+2a+3 2a^2+2a+3 2a+3 2a+3  1  1  1  1  1  1  1 2a^2+3a+1 3a^2+2a+3 a^2+3a a^2+3a+3 2a^2+3a+1 a^2+3a 3a^2+2a+3 a^2+3a+3 3a^2+2a+2 2a^2+3a+3 a^2+3a+1 a+2 3a^2+3 a^2+a a+2 3a^2+2a+2 3a^2+3 a^2+a a^2+3a+1 2a^2+3a+3 2a^2+3a 3a^2 a^2+1 a^2+a+3 2a^2+a+3 3a^2+a 2a^2+3a a^2+2 a^2+3a+2 3a^2+1 3a^2+3a+3 3a+1 2a 2a^2+a+2 3a^2 a^2+3a+2 a^2+1 2a^2+a+3 a^2+a+3 2a^2+2a+2 2a^2+a+2 a^2+2 3a+1 3a^2+a 3a^2+3a+3 3a^2+1 2a^2+2a+2 2a^2+2 2a^2+2
 0  0 2a^2+2 2a  2 2a^2 2a+2 2a^2+2a+2 2a^2+2a 2a 2a^2+2 2a^2+2a+2 2a+2 2a 2a^2  2 2a^2+2a  0 2a+2 2a^2 2a^2+2a+2 2a^2+2a  2 2a^2+2a+2 2a^2+2  0 2a  2  0  2 2a^2 2a^2+2  2 2a^2 2a^2+2a 2a+2 2a^2+2a 2a+2 2a^2+2  2  0 2a^2+2a+2 2a+2 2a^2+2a+2 2a^2+2 2a^2 2a+2 2a^2+2a 2a 2a 2a  0 2a^2+2 2a^2+2a+2 2a^2 2a^2+2 2a^2  0 2a+2 2a 2a^2+2a  0 2a^2+2a+2 2a^2 2a^2+2a+2 2a^2+2 2a^2+2a+2 2a+2  0 2a^2+2a  2 2a^2+2 2a+2 2a^2

generates a code of length 74 over GR(64,4) who´s minimum homogenous weight is 510.

Homogenous weight enumerator: w(x)=1x^0+12544x^510+2527x^512+3584x^518+12544x^526+1568x^528

The gray image is a code over GF(8) with n=592, k=5 and d=510.
This code was found by Heurico 1.16 in 69.3 seconds.