Ardun heads, I've seen and learned about them, but today I heard a rumor they were made for garbage trucks originally, to boost power 60%

the originals were built in England because they commissioned Zora Arkus Dontov and his bother to pump up the power of it's commercial fleet (garbage trucks)
https://www.jalopyjournal.com/forum/threads/when-did-ardun-heads-come-out.1038774/

is the rumor that seems to have no data to back it up

New York Times article was dated August 18, 1947.
https://www.jalopyjournal.com/forum/threads/when-did-ardun-heads-come-out.1038774/

tells the early history of the Ardun heads, and the rest is worth reading, but nothing is ever mentioned about garbage trucks.

https://books.google.com/books?id=S7E_gXmNbpAC&pg=PA139&lpg=PA139&dq=Ardun+White+Paper&source=bl&ots=KE0LNK9wBF&sig=lqQL-h8ImnMZs0fgBMH52bUVp5Y&hl=en&sa=X&ved=0ahUKEwiX1_vh443QAhVU92MKHfjYCPUQ6AEIQzAE#v=onepage&q&f=false

Sources of the rumor:

ARDUN cylinder heads, designed and built by Zora Arkus Duntov, for flathead Ford V8’s in NYC garbage trucks that were under powered. ZAD would later become a design engineer with GM on the Corvette https://catchmeifyoucan427.tumblr.com/post/181330225917/ardun-cylinder-heads-designed-and-built-by-zora
and https://www.fordbarn.com/forum/showthread.php?p=1477169

and then there is the frequent complaints about the Ardun heads:

The same book ( "Zora Arkus-Duntov The Legend Behind Corvette")  mentioned says it appears the Ardun heads had "a littany of problems, D. Randy Riggs, in an Automobile Quaterly aticle on Ardun wrote: "It's cast-steel pushrods weighed the same as a connecting rod, and valve seats came loose from expansion differences of the aluminum and bronze materials. The stock Ardun valves were too heavy. Exhaust manifolds were constricted and head gaskets were a common failure. The coke bottle shaped lifters were originally made from Buick components and had a tendancy to gall. Valve springs were inadequate. The two intake manifolds had no balance tube between them and were poorly designed. The spark plug tubes were a menace and the stock Ford ignition was not up to the task.""

It goes on to quote Ray Brock who said the heads did nothing to fix the age old overheating problem that Fords were known for.

https://www.jalopyjournal.com/forum/threads/blast-from-the-past-1947-popular-science-ardun-heads-for-flathead-fords.522221/

veteran English Rodder Ken Cooper said that the Ardun units were used on (some) refuse vehicles. He had some.

https://www.fordbarn.com/forum/showthread.php?p=1477169

Around 1941, (obviously the years are wrong, so the rest isn't reliable info either) ten years BEFORE Chrysler unveiled their first Hemi headed engine called the FirePower in 1951, the Ardun Company of New York "designed" a set of hemi-spherical heads for the Ford Flathead V8. Originally designed for military truck's, Ford Motor Company built these "hemi" engines for garbage trucks in London prior to switching to a less problematic and bigger Lincoln engine.
https://www.facebook.com/fordmenlegends/posts/685154864872025

https://books.google.com/books?id=paeyN79nV90C&pg=PA115&lpg=PA115&dq=ARDUN+heads+garbage+trucks&source=bl&ots=rJMkrijSps&sig=XHUwC7XHasVefEW7XfnT_vQaLkk&hl=en&sa=X&ved=2ahUKEwjQvKOzoLXfAhVhl1QKHbMAAuMQ6AEwCHoECAUQAQ#v=onepage&q&f=false

Ford Total Performance: Ford's Legendary High-Performance Street and Race Cars By Martyn L. Schorr
https://books.google.com/books?id=gsFQCgAAQBAJ&pg=PA13&lpg=PA13&dq=ARDUN+heads+garbage+trucks&source=bl&ots=LTZzLtjr3g&sig=0-DHx34fwy5c7woPPiTs0KUc34c&hl=en&sa=X&ved=2ahUKEwjQvKOzoLXfAhVhl1QKHbMAAuMQ6AEwCnoECAIQAQ#v=onepage&q&f=false


You can thank garbage trucks for the birth of not only some of the most legendary and coveted hot rod parts known to man in the form of Ardun cylinder heads but also for launching the career of a man who still stands as a giant long after his passing today, Zora Arkus-Duntov. We think of Ardun heads today as pieces used by hot rodders to make their cars faster and they were but the original intention of these babies was to crank the power level of garbage trucks being used in London up after Ford was granted a contract to supply them but their flathead V8s were not making enough power to meet the specs of the agreement. This overhead valve conversion got the power levels up and had the trucks meeting muster. Today, original Ardun heads are among the most prized pieces in the hot rodding universe.

https://bangshift.com/bangshift1320/watch-this-table-top-sized-ardun-headed-flattie-fire-up-and-run-the-sound-is-great/