Jan
And then there is the "atmospheric" intake valve.

AKA "Wheeze valve" really worked great in 200 rpm
Vaughn Garden Tractors.

Knight sleeve valve engines suffered from carbon
build-up in the sleeve's ports. Oil and fire took their
toll.

60 years back, Ford flatheads didn't need headers.
just dispense with exhaust manifolds. (neighbors
withstanding)

Old Chief Lynn