They both share esentially the same engine within a few HP. The difference is the gearing and weight (and of course, suspension). The Demon has 3.91 gears and is faster 1/4 mile (mid 11's in street trim) the Valiant weighs roughly 300lbs less and has a top end over 160 but the 2.73 gears make a bit of a slug off the line. A 5 speed trans and deeper gears would make the Valiant faster at both ends.