What should it run?

So for years I was using the Wallace calc as a guide...this one>

http://www.wallaceracing.com/accel-calc.php

With specs on both the cars I ran, the weight/mph/ET always came out as expected on the hp front but it was fly hp?......just as an example of this was the 340 Cuda....10.1 SCR, stock unported 2.02 heads, .590 solid purple cam, strip Dom, 850DP, 1.75 chassis hdrs. that came out at 375hp, the car ran 12.39@108, I used the approx weight of 3550lbs at the line ( all steel car, stock leafs), Cannot see that being 375rwhp with those specs which would make it 432 fly with only a 15% loss, can give you another example of the 440 car.....your thoughts