The Natural Philosopher wrote:

its rare to see more than 70bhp/liter from any normally aspirated road
engine.



Almost any bike.

Or if you want cars - Toyota 3SGE (in the MR2 Mk2 among others), 2
litres, 158BHP from the later UK models, and over 200 if you can get
hold of one of the Japan-only BEAMS engines. Though the last does have
variable valves etc...

Or the BMW 320, 150BHP/ 2 litres from 1991.

Or IIRC the Cavalier GSI, 156 BHP, 2 litres, and that's back a few years.

If you say normally aspirated, *carburettor* engine, then I'll let you
have it.

Andy.