Makes a big differenceJust so you know, the standard AV Bisharp spread is 64 HP, 252+ Atk, 192 SpD, this is a lot more effective at switching into special hits than your max hp 0 spd variant.
252 SpA Zapdos Heat Wave vs. 64 HP / 192 SpD Assault Vest Bisharp: 142-168 (49.4 - 58.5%) -- 98.8% chance to 2HKO
0 SpA Zapdos Heat Wave vs. 252 HP / 0 SpD Bisharp: 222-262 (66.4 - 78.4%) -- guaranteed 2HKO