A walker with total Armour value (front plus both sides plus rear) greater than 45 counts as ten models, otherwise they count as five models.
Enemy Morale
Source: 3rd-A-Palooza (3.5) Rulebook v1.4, p. 46
Source: 3rd-A-Palooza (3.5) Rulebook v1.4, p. 46
A walker with total Armour value (front plus both sides plus rear) greater than 45 counts as ten models, otherwise they count as five models.