The generator matrix

 1  0  0  1  1  1  0  4  1  1  1  2  1  6  0  1  1  1  1  4  4  2  1  1  6  6  1  1  6  4  6  1  1  2  1  1  2  1  0  1  2  1  2  1  2  4  1  1  0  1  1  1  1  4  6  4  1  1  4  0  1  1  1  1
 0  1  0  0  1  3  1  6  2  1  2  1  7  1  0  5  4  6  7  1  1  1  3  0  6  1  6  2  1  1  0  7  4  1  7  0  4  5  1  3  0  6  1  1  1  2  6  4  1  7  6  3  7  1  1  1  3  0  1  1  4  3  2  5
 0  0  1  1  1  4  5  1  5  2  6  2  3  7  1  2  4  7  7  3  4  1  2  6  1  2  5  7  4  3  1  0  6  4  0  2  1  4  2  5  1  1  7  1  4  1  6  4  0  0  0  6  5  7  7  6  1  5  6  2  7  5  2  0
 0  0  0  2  6  0  6  6  6  0  0  4  2  2  6  2  6  4  4  4  2  0  2  2  0  6  2  0  6  6  2  6  4  4  2  6  4  4  0  0  6  4  4  6  2  4  6  0  2  4  0  2  2  6  4  2  0  6  2  4  6  6  6  6
 0  0  0  0  4  0  4  4  4  4  4  4  0  0  0  4  0  4  0  4  0  0  0  4  4  0  4  0  4  0  4  0  4  4  4  4  0  0  0  4  4  0  0  0  4  0  0  4  4  4  4  4  0  4  4  4  0  0  0  4  0  4  4  0

generates a code of length 64 over Z8 who´s minimum homogenous weight is 58.

Homogenous weight enumerator: w(x)=1x^0+203x^58+128x^59+623x^60+244x^61+550x^62+204x^63+568x^64+164x^65+440x^66+112x^67+327x^68+84x^69+172x^70+68x^71+133x^72+20x^73+41x^74+10x^76+2x^78+2x^80

The gray image is a code over GF(2) with n=256, k=12 and d=116.
This code was found by Heurico 1.16 in 0.675 seconds.