Just for fun, I'm still thinking of ways that one could build a rocket that would have the readily verifiable characteristics of the Saturn V, yet still be unable to make it to the claimed cutoff velocity for the S-IC stage.
The fatal flaw that makes it impossible, of course, are the readily observed shock clouds forming just as the stack approaches Mach 1. But let's say NASA has some fiendish way to fake those too. Besides, the average person doesn't understand supersonic fluid flow, therefore all that science is bogus and can be ignored.
"Readily verifiable" includes the external dimensions of the entire rocket, the height of the launch tower, and the liftoff acceleration. We can include the known physical properties of kerosene and liquid oxygen, and we can assume Newton's laws of motion and Tsiolkovsky's rocket equation are correct. It would not include any mass, thrust or engine Isp figures as those are obvious NASA propaganda. Dummy upper stages (e.g., containing extra propellants for sub-performing first stage engines) would be permitted as it's assumed the eyewitnesses could not verify proper operation of the S-II and S-IVB stages.
We can assume that NASA would not secretly sabotage their rocket to lower its performance, as the whole point is to fake a better-performing rocket than the one they were able to build.
Have at it...
