I've tried, about as ball park as the rest of the internet. 6 - 10 hp per 100 pounds. That for a 1000 pounds, say going from a 4200 pound Fury to a 3200 pound Duster would tell you that 60-100 hp would be needed. So what is it? 60 or 100 hp needed??? Big range there and what you would need to buy to get it....
