Aha! That got your attention, didn't it?
This goes back to the XJ13 thread, which drew enough response to merit a small follow-up: in his otherwise super book on Jaguar saloon cars, Paul Skilleter claimed that the competition 5-litre V-12 had been developed to produce over 800 hp. Reading around the subject, I found that designer Walter Hassan - writing in his AUEW booklet Jaguar v12 engine - its design and background - actually claimed 502 bhp/205 lb/in2 BMEP (p.15), which was then restated as 802 bhp a page later.
Clearly, at least one excellent and well-informed writer has fallen foul of a simple type-setting error!
Now, there must be many other similarly-generated (and perhaps more interesting) legends out there...