they were used in ww2 by us troops

many of them were probs left over in europe too when we withdrawed from the western front

knuckleads were produced from 1938 to at least 1942

https://ultimatemotorcycling.com/2014/11/10/harley-davidson-knucklehead-classic-motorcycle-tales/

the engine was an oddity att

because it was an OHV engine and not a flathead

so apparently according to this it was first produced in 1936 and ended production in 1948

remember this was during a time when flatheads were basically universal

so this motorcycle could literally beat almost any german bike on the road

to put this in perspective, GM produced its first OHV engine in 1949

ford in 1953

packard in 1955

chrysler in 1955

although i could be wrong about chrysler

yeah no chrysler started OHV production in 1951

on the left is a flathead engine also called an L-Head, on the right is an OHV engine

OHV standfs for overhead valve

the problem with flatheads was despite the lower cost of production and simplicity of design it was limited in horsepower and efficiency

because the fuel mixture had to go up to the side and into the cylinder efficiency was horrible and compression was extremely low

leading to gas guzzling tendencies and higher emissions alongside slow speeds and low horsepower, which was a problem in the post war economy due to the trend in larger heavier vehicles for growing family households

the T valve flatheads had a particularly bad habbit of emitting high amounts of NOS gas due to insufficient combustion in the cylinder

during the horsepower wars in the mid 50s to the early 70s engines in the 60s started going through some radical developments due to chrysler's new 426 hemi in 1964

places like ford and gm started making their own performance engines in the mid 60s to early 70s

ford came out with its SOHC version of their 472 FE V8 in late 1964

it was the first successful Single Overhead Camshaft engine produced

and it put out 657 gross horsepower when fitted with dual quads

that vastly overshadowed chryslers 426 hemi that only plut out 425 HP at max

oldsmobile started experimenting with DOHC or double overhead camshaft engines in the late 60s with the W43 engine

but the project was shut down due to the damned government emissions regulations and fuel crisis

btw the ford SOHC engine was dubbed the 472 Cammer to differentiate it from their OHV counterparts

this is the difference in said designs

the latter two are more powerful due to the increase of valves

SOHC and DOHC have two intake and two exaust valves

OHV has only one of each

DOHC has a mechanical advantage over SOHC

and thats because if one camshaft rockers break in one cylinder....

there are still the other set pof valves that keeps the cylinder functioning

almost all vehicles nowdays are powered by a DOHC engine

sorry if i'm flooding the chat with all this technical stuff 😅

my dad and grandpa worked for chrysler before the plant shut down