The generator matrix

 1  0  1  1  1  1  1  1  1  1  1  1  1  1  1  7  1  1  1  1  1  1  1 21  1  1  1  1  1  1  1 14  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 42  1  1  1  1  1  1  1  1
 0  1 36 31 16 48  4 19  7 29 38  9  6 46 26  1 21 43  3 23 20 11 40  1 14 15 45 16 48  4 19  1  9  6 46 26 44 13 32 33 42 22 24 28  8 10  2 41 39 12 35  1 17 37 27 11 47 25 30 34  5  0 36  1  7 29 18 21 43 23 20 40

generates a code of length 72 over Z49 who´s minimum homogenous weight is 428.

Homogenous weight enumerator: w(x)=1x^0+756x^428+210x^430+294x^432+36x^434+1008x^435+84x^437+6x^455+6x^469

The gray image is a code over GF(7) with n=504, k=4 and d=428.
This code was found by Heurico 1.16 in 39.7 seconds.