Those Huck drums are getting harder to find. You might try an ad in swapmeet forum here. Nobody makes an 8 lug disc brake kit...some have done the conversion themselves. The search function will turn up a lot.
You might also consider upgrading your front brakes to Bendix, which replaced the old Huck brakes on medium duty trucks in 1953. Parts are more available and they will also be 12". Your stock front brakes are 11".
