well there are alot of factors we need to know to see what you should run. My mild 440 in a 74cuda with stock susp run 11.50's @116-117mph. I run a 1.55-1.58 60ft. 3500 stall 3.91 gears. Your cam should get you in 11's. What heads, Int, carb, gears, fuel system, tires are you runnin? Something not right here? Maybe starving for fuel?Like was said maybe not 550hp. Timing should be at least 36 degrees all in by 2000 rpm. My opinion. Good luck!