The generator matrix

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

generates a code of length 63 over GR(64,4) who´s minimum homogenous weight is 431.

Homogenous weight enumerator: w(x)=1x^0+3360x^431+1204x^432+6272x^433+4032x^439+1246x^440+1792x^441+6944x^447+1547x^448+6272x^449+84x^456+14x^472

The gray image is a code over GF(8) with n=504, k=5 and d=431.
This code was found by Heurico 1.16 in 14 seconds.