Toping a lowryder #2 ak47

if i toped a lowryder how long would it take to grow out

It would begin growing out right away, you just wouldn't see it for a few days. Have you looked into LST(low stress training) supercropping? Bending the plant over and saving your most developed top for harvest, while achieving the same goal as topping.. Check it out before you cut.

ya i know about supercropping and a little about Lst