what do you believe to be accurate?

i've read all these resistance posts and i have this to ask.

if you put a lightweight flywheel--without any other mods--on a 5.0 would your rwhp decrease?
you are accelerating the engine faster, which you say would increase resistance.

after spending 12 weeks of school dynoing cars on a chassis dyno i saw many a stock vehicle climb on the dyno and put out--you guessed it about 30hp lower than the factory number. examples are as follows:

91 mustang--factory rating of 225hp--dyno 195hp
95 cobra--factory rating of 240hp--dyno 208hp
99 M3--factory rating of 240hp--dyno 215hp
95 t/a--factory rating of 275hp--dyno 240hp
88 325is--factory rating of 189hp--dyno 162hp

big deal you say--those are all around 15%. lets examine some factory hot rods.

06 Z06--factory rating of 505hp--dyno at vette doctors 474hp--approx 7% loss
03/04 cobras--factory rating of 390hp--typically dyno 360hp
03/04 mach 1--factory rating of 305hp--dyno at shm 278hp
02 camaro ss--factory rating of 320hp--dyno 305hp

i do agree it is very hard to say 100% without back to back testing, but if you look at factory hp numbers vs. stock rwhp numbers, it is pretty convincing.

another important note is torque on all the vehicles above does not drop as much as the hp--very interesting.

i find this interesting due to the fact that the vehicles equipped with shorter or two piece driveshafts lose less torque.