So I had a commenter earlier (Hi Ben, o wizard of DIY EVs!) say that I should put a forklift motor on my go-kart. Well, Ben…it’s been done. Now this guy has a “race cart,” which is different from what I’ve got. However, he did just what you suggested – and the results are pretty crazy.
Side note: 70,000 Watts is ~94 HP. With driver, that cart probably weighs about 400 lbs. That’s roughly 4.255 lbs/hp, if you’re into power-to-weight ratios.