The generator matrix

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

generates a code of length 28 over GR(64,4) who´s minimum homogenous weight is 183.

Homogenous weight enumerator: w(x)=1x^0+1344x^183+16506x^184+3360x^185+896x^189+8064x^191+55223x^192+6720x^193+28672x^196+6272x^197+19264x^199+104328x^200+11424x^201+14x^216+56x^224

The gray image is a code over GF(8) with n=224, k=6 and d=183.
This code was found by Heurico 1.16 in 4.3 seconds.