2003 Ford mustang gt stock horsepower Source Source Source Source Source Source Source Source Source Source Read Also: How much horsepower does a 2003 ford mustang gt have How much horsepower does a 2003 ford mustang cobra have 2003 Ford mustang gt horsepower 2003 Ford mustang mach 1 horsepower 2003 Ford mustang cobra horsepower 2004 Ford mustang gt stock horsepower