Ok, I was playing around with this and noticed that when i put in that the exhaust is small tube headers with mufflers the HP and TQ readings are signifigantly lower then if i used small tube headers with open exhaust... Obviously the program cant be exact but the readings differ from about 386HP and 407ft Lbs of TQ to--- 411HP and 425ft Lbs, that is a huge difference, what is the auctual difference in real life about??

 

Not sure if anyone can accurately give you an answer because every combination is different. Open exhaust means headers with tuned collectors.

So for a street car you can forget that. The figures are if the engine was on a dyno. Me, I just run the small tube headers with mufflers. When I run my combination through DynoSim I come up with 509hp and 485tq. We shall see as my motor is ready for the install.