The generator matrix

 1  0  0  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1 2a^2+2  1  2  1  1 2a^2+2a+2  1  1  1  1  1  1  1  1  1  1  1  1  1 2a^2+2a  1  1  1  1  1  1  1  1  1  1  1  1  1  1 2a^2+2a  1  1  1  1  1  1  1 2a+2  1  1  1  1  0  1
 0  1  0 2a^2+2 2a 2a^2+2a  2 2a^2+2a+2 2a+2 2a^2  1 2a^2+a+2 a^2 2a^2+3 2a^2+3a+2 3a^2+2 3a^2+3a+1  3 2a^2+3a a^2+3a+3 a^2+2  1 a^2+a+1  1 a+2 2a^2+1  1 3a^2+1 3a^2+2a+1 3a^2+3a+3 a^2+3 3a^2+3 2a^2+a+3  a 2a^2+a+1 2a+1 a^2+3a+1 a+3 a+2 2a^2+a+1  1 a^2+2a a^2+3a+2 a^2+1 3a^2+3a+2 3a^2+a+2 a^2+2a 3a^2+a 3a^2+2a 3a+3 2a^2+2a+3 a^2+a+3 3a+1 3a^2+a+2 3a^2+3a  1 a^2+1 a+1 2a^2+3a+2 a^2 3a^2+3 2a+1 3a^2+a  1 a^2+3a+1  3 a^2+2a+3 2a^2+2  1 a^2+2a+3
 0  0  1  1  a a^2 3a+3 a^2+3a a^2+3a+3 a^2+2a+1 a^2+2a+3 3a^2+2a+1 a^2+1 a^2+3a+1 2a^2+3 2a^2+a+1 a^2+2a 3a^2+2a+2 3a^2+3a+2 a+2 a^2+a+2 2a+1 a^2+a+3 a+1 3a+1 3a 3a^2+3a+3 3a^2+a+1 2a^2+3a+3 3a^2+a+2 2a+1 2a^2+a 2a+3 3a^2 2a^2+2a 2a+2 2a^2 a+3 a^2+3a+3 a^2+2a+1 3a^2+2 3a^2+2a+2 a^2+2a+2 2a^2+2a+2 2a^2+3a a^2+3a+2 3a  3 3a^2+a+1 a^2+3a 2a^2+1 2a^2+3a+1 3a^2+a+3 3a^2+1 2a^2+3a+3 2a^2+a+2 3a^2+3 2a^2+3a 2a^2+2 2a^2+1 a^2+2 a^2+a 2a+2 a^2+2a+1 a^2+2a+3 3a+1 3a^2+a 2a^2+2a+1 2a^2+3a+1 2a^2+3a+1

generates a code of length 70 over GR(64,4) who´s minimum homogenous weight is 474.

Homogenous weight enumerator: w(x)=1x^0+7896x^474+9912x^475+5880x^476+168x^477+84x^480+28056x^482+24920x^483+12208x^484+1008x^485+189x^488+38472x^490+29288x^491+11704x^492+2408x^493+231x^496+43848x^498+32648x^499+13216x^500+7x^536

The gray image is a code over GF(8) with n=560, k=6 and d=474.
This code was found by Heurico 1.16 in 13.9 seconds.