The generator matrix

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

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

Homogenous weight enumerator: w(x)=1x^0+196x^68+38x^72+20x^76+1x^80

The gray image is a code over GF(2) with n=276, k=8 and d=136.
This code was found by Heurico 1.16 in 0.13 seconds.