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  1  1  1  1  1  1
 0  2  0  0  0  2  2  2 2a  0  2 2a 2a 2a 2a  2 2a 2a^2+2a+2  0  0  2 2a^2+2 2a^2+2a+2 2a+2 2a^2 2a+2  0 2a+2 2a^2 2a^2 2a^2+2a+2 2a^2+2a+2  2  2 2a+2 2a  2 2a+2 2a  0
 0  0  2  0  0 2a^2+2 2a^2+2a+2 2a^2+2a 2a^2+2a  2 2a+2 2a^2+2  0  2 2a^2+2a+2 2a^2 2a 2a^2+2 2a^2 2a  0 2a^2+2a  2  0 2a^2+2a 2a^2 2a^2 2a^2+2 2a^2  0 2a^2+2 2a^2+2a+2 2a^2+2 2a^2+2a+2 2a+2 2a 2a+2 2a^2+2 2a^2+2  0
 0  0  0  2  0  2 2a^2+2a+2 2a 2a+2 2a^2 2a^2+2  0 2a^2+2a+2  2 2a 2a^2+2a 2a^2+2a 2a^2+2a  2 2a^2+2a 2a 2a 2a^2+2a 2a^2+2a 2a+2  0 2a^2  0 2a^2+2a  2  0  2 2a 2a^2+2a 2a^2  2  2 2a^2 2a^2 2a
 0  0  0  0  2 2a^2+2 2a+2 2a 2a^2+2a+2 2a 2a^2 2a^2 2a+2  0 2a  0 2a^2 2a^2+2a 2a^2+2a  2 2a+2 2a^2+2a+2 2a^2+2 2a+2  2 2a 2a^2+2 2a^2  2 2a^2 2a^2+2a+2 2a  2 2a^2+2a 2a+2  0 2a+2 2a+2 2a^2+2a 2a^2

generates a code of length 40 over GR(64,4) who´s minimum homogenous weight is 240.

Homogenous weight enumerator: w(x)=1x^0+329x^240+1680x^248+2674x^256+3318x^264+3584x^266+4529x^272+50176x^274+5733x^280+175616x^282+5978x^288+5040x^296+2492x^304+917x^312+77x^320

The gray image is a code over GF(8) with n=320, k=6 and d=240.
This code was found by Heurico 1.16 in 23.4 seconds.