Top speed on a1977 kz1000 ltd 160 mph compare to newer kz 1000 of 130 to 132 mph 78,79,80 years i have these years. is the square heads more heavy duty cams because i notice that round heads bikes the motor spins more freely. The 77 ltd has felt stronger and quicker but not been able to test like the other. Since i just purchased. It and