Horsepower change from 1971 to 1972?

[Silvius]

I have not been able to find a definitive answer on whether horsepower actually dropped from 1971 to 1972 models. I know the rating methodology was different; a 1971 350 was rated at 255 gross horsepower and the 1972 was rated at 175 net horsepower. While I understand that the ratings were changing in the industry at that time, my question is:

Was compression lowered for these trucks in 1972?

Was the actual horsepower the same from 1971 to 1972?

The answer may already be on the board, but I didn't find it in my searches; only explanations of the different methodologies.

Thanks for any help!