Scored this the other day, repro unfortunately but interesting just the same. It's a copy of a genuine Triumph publication as can be seen, and therefore can be viewed as somewhat of a gospel. It's well known that companies of the time could be a little imaginative with their claims, and road test bikes were specially prepared before the press got their hands on 'em, but the graph beggars belief. 31 BHP out of a standard 500 of 1951, even at the crank takes some believing, but 43 after fitting the parts is a huge leap of faith.
These are the only parts needed they claimed, available direct from the factory, although they do say the engine and frame numbers must be provided. They could be pretty confident that there were not many Heenan and Froude brake testers available to the average rider, and therefore difficult to disprove, but, Joe Craig, Francis Beart and the other tuners of the day reckoned that 100 BHP per litre was bloody good going. 43 from a tweked road bike, from a factory without a racing programme of it's own, kinda makes you wonder.