if this were the case, i would rethink the gearing.
my guesses at 70 mph up a 6% grade, 800 lbs GVWR, about 15 hp. 70 mph, at 1000 GVWR, about 7 hp. 0-60 in 2 seconds, about 250 hp (assuming you could still weigh in at 800 lbs). beyond supercar territory. 0-60 in 4 seconds, 100 hp. 6 seconds...