Crockpot recipe when converting temperature from low to high?
You can probably get away with high heat, but you need to watch the liquid content. Since you're not cooking something that is liquid and can circulate to heat evenly, you risk burning the food or having it dry out.

I can't see any reason this needs to cook for such a long time. Ground beef is finely divided, so cooking for extended times won't benefit it that much. I'd say bring it to a boil either on high in the crock pot or on the stove, then transfer to the crockpot for 2+ hours (as long as you have).