The generator matrix

 1  0  1  1  1  1  1  1
 0  1  1  a a^6*X+a^2 a^3 a^6*X+a^6 a^3
 0  0 a^6*X  0  X  X a^4*X a^5*X
 0  0  0  X a^6*X a^5*X a*X  X

generates a code of length 8 over F8[X]/(X^2) who´s minimum homogenous weight is 40.

Homogenous weight enumerator: w(x)=1x^0+392x^40+448x^42+588x^48+21504x^49+6272x^50+59080x^56+150528x^57+21952x^58+1379x^64

The gray image is a linear code over GF(8) with n=64, k=6 and d=40.
This code was found by Heurico 1.16 in 0.565 seconds.