I remember they used a measurement called SAE which was changed to DIN in the early seventies for BHP figures.
The DIN figure was lower......and supposedly more accurate. No idea what the letters stand for.
SAE - Society of Automotive Engineers and is American. They tested engines without any accessories, so the figures ought to be higher.
DIN - Deutsches Institut fur Norming and is German adopted by Europe. It's the equivalent of British Standards, whose requirements were used for other tests. DIN tests were as installed in the car, and so should be smaller numbers than SAE. The actual measured/calculated amount should be interchangeable.
It doesn't change the fact that 160bhp from a 2.8i(which is DIN figure) requires a much higher state of tune than Ford ever sold, or that a '127bhp' Sprint was disappointingly slow for its claimed power. They were supposed to be badged as Dolomite 135, but even Triumph knew they couldn't get away with that. The Sprint head picks up the crap engineering of the slant four and adds even more stupid ideas.
This all without going into the utterly ridiculous BHP unit itself.