Many times it's something simple, a kinked line (especially in a hard to reach/see area), a plugged filter, or the wrong/not enough pump. Especially if the car feels strong on the initial launch and maybe low gears then falls off or even flat on it's face. On the higher powered cars many times it's the original fuel lines being too small. A lot of people do not think about the fact that if your car is capable of a fast launch, the fuel has to fight the G forces of that acceleration and if the pump is not strong enough it can starve the carb. Just a heads up for future trouble shooting. Mark L