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

generates a code of length 81 over Z8 who´s minimum homogenous weight is 68.

Homogenous weight enumerator: w(x)=1x^0+57x^68+4x^69+48x^70+12x^71+114x^72+40x^73+90x^74+86x^75+101x^76+124x^77+328x^78+162x^79+835x^80+176x^81+847x^82+156x^83+313x^84+124x^85+74x^86+80x^87+51x^88+40x^89+58x^90+14x^91+35x^92+4x^93+52x^94+2x^95+20x^96+25x^98+6x^100+10x^102+3x^104+3x^106+1x^122

The gray image is a code over GF(2) with n=324, k=12 and d=136.
This code was found by Heurico 1.16 in 2.05 seconds.