The generator matrix

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

generates a code of length 8 over GR(64,4) who´s minimum homogenous weight is 48.

Homogenous weight enumerator: w(x)=1x^0+196x^48+3584x^49+3696x^56+25088x^57+203x^64

The gray image is a code over GF(8) with n=64, k=5 and d=48.
This code was found by Heurico 1.16 in 0.00811 seconds.