The generator matrix

 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  2  2  0  2  2  4  2  2  0  4  4  4  0  0  2  2  2  0  4  2  2  2  0  4  2  2  2  2  1  1  1  1  1  1  1  1  2
 0  2  0  2  0  0  2  2  4  4  6  6  4  4  6  6  0  4  2  6  0  4  2  6  4  0  6  2  4  0  6  2  4  2  2  0  6  2  6  6  0  4  2  2  2  2  2  4  0  4  0  6  2  2  2  2  0  0  4  4  0  0  4  4  4  4  0  2  6
 0  0  2  2  4  6  6  4  4  2  6  0  0  6  2  4  0  2  2  0  4  6  6  4  4  6  6  4  0  2  2  0  2  2  4  2  2  0  0  4  2  2  2  6  6  2  6  6  6  2  2  6  4  0  0  4  0  4  4  0  0  4  4  0  2  6  6  2  4

generates a code of length 69 over Z8 who´s minimum homogenous weight is 68.

Homogenous weight enumerator: w(x)=1x^0+43x^68+32x^69+36x^70+9x^72+4x^74+1x^76+2x^80

The gray image is a code over GF(2) with n=276, k=7 and d=136.
This code was found by Heurico 1.16 in 0.0935 seconds.