/ 252 Defense / 252 Special Defense / 4 HP /
The HP investment looks tempting, but having a lot more HP over Defenses actually weakens your bulk. Only fully invest HP if your Defending stats are about 20 points within range of each other.
Pokemon like Dusclops have proved that jamming a lot of Defenses (130 in both) into a little HP (40) makes for a bulky wall.