posted by Don Kincl
Ardun hemi heads for the Ford flathead V8 have become legendary. They are very rare, and equally expensive. During the early-mid 50s, when Detroit’s new crop of ohv V8s were just becoming more available, a set of Ardun heads was the way to stay competitive.
The Ardun heads’ origin myth is not perfectly and consistently documented in every detail, but one can piece together enough elements to create a pretty clear picture. One thing is undisputed: they were originally designed to give Ford’s flathead V8 truck engines a significant boost in power, supposedly for an export order of garbage trucks being sent to Great Britain. That part seems a bit odd, but there’s some references to that. In any case, we do know that Ford passed on them (serious reliability concerns) and solved their truck power deficit by making the larger 336 c.i. Lincoln flahead V8 available in their trucks for 1949. The Duntov brothers then started to target the hot rod market.
The reference to “aircraft power” is because almost all aviation engines back then used hemi heads to optimize power output. But then there were of course some American cars that used them too, like the Duesenberg and other high performance models and racers. There had been hemi heads available for the Model T for some years.
Here’s a NYT article from August 18, 1947 about the near-completion of the Ardun heads. What’s not disputed is that recent Russian emigre George Kurdasch did the actual drafting of the heads.
This snippet is from the book “Ford Total Performance” by Martin L. Schorr. I find it somewhat questionable, for a couple of reasons: British trucks (and all over the continent) back then were generally of very modest power; less than even in the US. And it mentions that these were for London, and issues with climbing hills. There are essentially no hills in London. I find it quite unlikely that London would be importing garbage trucks from the US in the first place right after the war, when hard currency for imports was a serious problem. And if so, power seems unlikely to have been a big concern.
But it makes for a good story, although there’s absolutely no reference to it in the NYT article. And it’s certainly quite possible that one or more Ardun equipped engines found their way into trucks there, as the actual building of the Ardun heads was contracted to a firm in England.
If I had to guess, the Duntovs created the hemi heads on speculation, hoping to interest Ford generally, or possibly as a re-power alternative to existing trucks, as gas engines in trucks back then had a rather short service life and replacing them after some 30-50k hard miles was just par for the course.
Another reason given for Ford’s supposed cold shoulder was that the big and wide Ardun heads would never have fit into the rather slim engine compartments of their passenger cars and light trucks.
In any case, the early Ardun heads were quite problematic. D. Randy Riggs, in an Automobile Quarterly article on Ardun wrote: “Its 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 tendency 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.”
Ardun also created a version for the smaller Ford V8-60, and these were targeted to midgets, sports cars and such from the get-go.
These were eventually reverse-engineered (copied) for the Brazilian Simca Chambord, where it was made until about 1968 there, when it was finally replaced by the Chrysler 318 V8.
WOW! What history! I never knew of these conversions. As one who sold vocational application trucks starting in the 1960’s, any use of a Ford V8 seems ridiculous for the amount of power and the durability of the engine. For the garbage trucks in London, these cubic yard capacity could not have been much in order for these engines to survive. Just fascinating for me. Thanks, Paul.
I had heard of these heads, but knew very little about them. Thanks for filling in some blank spaces.
Thanks for the information; far more than I remember ever reading about these conversions before! Great article!! :):) DFO
I was well aware of these as a teenager, thanks to my uncle’s stack of Rod & Custom magazines from the late 60’s. I remember reading how the guys campaigning the C-T Roadster solved most of the power and reliability issues themselves. What a cool time to be a car guy!
Now you can buy brand new Ardun heads, the complete kit is $14,950
https://www.ardun.com/
For a truly unique retro-rod, dropping fifteen large on Ardun heads for a flathead doesn’t sound all that bad. A SBC would be far cheaper, but nowhere near as cool.
OTOH, someone wanting to go that route might as well just use an old Chrysler FirePower.
A Packard Straight Eight Thunderbolt had a displacement of 359 cubic inches and was rated at 212 horsepower. That would be unique in a retro-rod. No fiddling with exhaust pipe length and twisting headers for sure!
The renown ARDUN hemisperical heads for the flathead Ford were certainly a hot-rodders’ dream but apparently “a beautiful hypothesis slain by an ugly fact,” as they say: unreliability and low durability. It was certainly a beautiful engine, but the Chrysler Firepower became the answer to the question of volumetric efficiency and thus became the standard for power until the late 426 Hemi came along. Chrysler reliability was well-established, too.
I learned a lot of car things from my Dad, but he wasn’t much for Fords, so it is only here where I learned of the flathead Ford’s cooling issues.
So it’s a bit fascinating to start with that, and end with the litany of problems in the Riggs article near the end of this post.
I never knew these engines were meant for trucks. I figured Zora whipped them up to increase the competitiveness of the Allards he was building.
I can’t remember which Australian magazine perhaps Street Machine had an article about a new old stock kit dating from the late 40’s found in Adelaide South Australia.
Part of a batch imported and used on orchard trucks to climb a hill outside of Adelaide.
Post war getting a new truck in the British Commonwealth would have been impossible unless it was a war surplus GMC or Morris all wheel drive.
The duty on a new American truck would have been massive in Australia as tariffs would have favoured English and Canadian trucks.
I guessing an Ardun kit would have given a 30’s Ford truck performance comparable with a new truck a fraction of the cost even when factoring the duty on the US made kits.
Instead of the Skybolt OHV conversion, I would have liked to see Studebaker put a hemi head on their 170 C.I.D. six. Would have been able to use larger valves over that 3″ bore. Expensive to build, yes. I figure they could have gone for quite a few years with the original lightweight block though.
The well-known British racing driver Sidney Allard had a workshop that provided maintenance for the Ford garbage trucks used by the London authority. Trying to sell his sports cars in the US, he found about the Ardun heads and decided to reproduce them for refitting those lorries. Also he wanted to apply them in road competition. A thorough redesign was neccessary and Duntov worked with Allard for some time. Unfortunately the
truck deal did not materialize and eventually Sidney sold his stock to Pierre Ferry, the French racer and builder of speed gear. Somehow, Jack Pasteur, the head engineer for the Brazilian Simca factory found those heads and brought them to South America where they where adapted for Simca Chambord.
I knew nothing of this. A few leading edge technologies in one were bound to have teething issues. Dropped valve seat inserts were one of the issues with early aluminum heads, even as late as Corvair.
What was the compression ratio of these ARDUN head engines?
Pretty cool .
Dropped valve seats was also a problem in aftermarket air cooled 160CC VW cylinder heads, most notably the Brazilian ones .
Easily rectified by any competent machine shop .
I remember Ardun powered Hot Rods in the 1960’s nice to see someone is still making them .
-Nate
I was fascinated to learn that Ardun had offices on the northern edge of Hell’s Kitchen in NYC. I had also not realized that ArDun was the contraction of Arkus Duntov. The Brazilian Simca application? News to me.
I knew about Duntov and his heads. I exceeded that knowledge in about 5 minutes reading this post. Good historyl
Willing to bet the sbc had as much to do with the death of the Ardun head as lack of engineering competence or accumulated reliaibility problems. Memory tells me they had the same customers. The 265 was a shock but the 283 was groundbreaking.