One of the fascinating, but lesser known, vintage motorcycle engines is the Moto Guzzi 500cc V8, built for racing from 1955 to 1957. It was a 90 degree DOHC with 8 individual Dell'Orto carburetors. In 1955, it produced 68 hp at 12,000 rpm and in its final configuration in 1957, put out 72 hp at 12 grand and probably sounded wonderful while doing so. Interestingly, it began with a 6 speed gearbox, then dropped to a 5 speed and finally ran as a 4 speed.
The motorcycle was raced with 2 different fairings, one much like a modern fairing leaving the front wheel exposed and the other, the famous "dustbin" with greater coverage, the choice depending on the track.
Though development was progressing nicely, Moto Guzzi withdrew from racing after 1957 so I guess we'll never know how it might have done in later years.
A lot of early engineering was far more impressive than some folks might think. High tech racing isn't some recent development, the guys were hard at work building bikes like this 60 and 70 years ago. With some of the recent V8 motorcycles sporting huge automotive engines, you might get the impression they all have to be massive hulks but there have been some beauties over the years like the Morbidelli V8 and the Yamaha based V8s built by Ian Drysdale. The Moto Guzzi goes back quite a bit further. I like it a lot.