What;s the deal on the different 5.0's?

They actually have the same power, but i think ford just decided to stop being lazy and correct the horsepower ratings. I've heard that when mustangs were converted to a Mass Air instead of speed density air metering system ('89 for all 5.0's, '88 for california 5.0's) the mass air flow meter actually costed about 3 horsepower because it was a minor restriction in the intake, and i think that there was a camshaft revision in the early 90's that dropped horsepower by 5 (...math doesn't add up, so there's probably something else or my numbers are off...whatever). This is just what i've heard though and have nothing to back this up. I guess ford just re-measured it or something, there wasn't anything specific in '94 that would cause the ratings to change i believe.

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'84 Mustang 5.0 LX
My car