By on May 3, 2015


After battling a “long-term illness,” former Chrysler engineer and “Godfather of the 426 Hemi,” Tom Hoover passed away on April 30. He was 85

According to Hemmings, Hoover joined Chrysler in 1955 to work on the Bendix Electrojector system, an early electronic fuel injection system that ultimately proved to be fraught with issues. His next assignment took him to the engine lab to work on an English straight-six engine for evaluation. However, it was his later connection with drag racing that made Hoover a known quantity outside of Chrysler.

The rest of Tom Hoover’s story can be found at Hemmings.

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30 Comments on “Tom Hoover, “Godfather of the 426 Hemi,” Dies at 85...”

  • avatar

    Snapshot of Peak America: BCGs, white shirts and skinny ties.

  • avatar

    Lead with “Godfather of the Hemi” and select a photo of him with a Max Wedge. There must be plenty of photos of the man with an actual hemi.

  • avatar

    He will be missed.

  • avatar

    what was so good about the HEMI? I mean the technological advantage?

    I know it had the hemispherical shape, but from a thermodynamic point that was not good. and from what i knoow (unless I’m wrong) HEMI in recent years was just a name since the motors didn’t have the hemispherical shape anymore.

    • 0 avatar

      OK …. this has to be one of the most ridiculous comments I’ve seen here in a while. Bad thermodynamically?? NOT! Since it is a crossflow head, there is less heat absorbed by the head and more is passed directly out the exhaust. Also, the hemi allows for large valves, increasing efficiency. Since an engine is nothing but a glorified airpump, everything done up top in a hemi is vastly superior to a side-by-side arrangement. The path both in and out is almost direct with fewer kinks.

      And yes, the newer Chrysler hemis are still hemis. Where did you get the idea they weren’t????

    • 0 avatar

      A canted valve arrangement is the hemi’s biggest advantage as you could fit bigger valves and as they moved toward the middle of the chamber they would not suffer from the sort of shrouding a parallel valve engine would. The central spark plug is probably the next best feature but the overall hemi chamber itself isn’t all that great since an engine with monster ports and huge valves needs alot Of quench to keep everything mixed up plus a hemi chamber needs a fairly large dome on the piston to build compressiob.

      Ford definitely had a better idea with the Boss 429 crescent head. That head was a truncated hemi that allowed more quench and had less chamber volume.

      The late model hemi is more of crescent combustion chamber but as any LS/LT fan will point out the hemi’s advantaged in a street application are negligible as GM’s heads work just as well and are cheaper to produce.

      The same with any 4 valve head. They allow excellent airflow with a tight chamber and a central spark plug with the added bonus of better low and mid lift figures. Peak flow number are generally close enough that it doesn’t matter especially since a cam will spend little time there.

      The Hemi does get good marks for power density though as it is a little larger than GM’s LS/LT engines and more compact than Ford’s MOD/Coyote engines for a given displacement.

    • 0 avatar

      I think you can find the answer to your question here:

    • 0 avatar

      mmh. according to Wikipedia I can’t tell much of an advantage, especially since HEMI seems to be limited to 2-valve technology. So is it correct to assume the recent “HEMI” engines are 2-valve motors?

      is there any real life evidence the HEMI is more efficient compared to an “everythign else equal” non-HEMI engine?

      And unless Wiki lies, hemi motors were used since 1901 by various manufacturers.

      • 0 avatar
        heavy handle

        Hemi designs haven’t been cutting-edge since the immediate post-war era, but that’s not the point. They were better (although heavier and more expensive) than the competing post-war American V8s, and that made them winners. Their competition on the drag strip and in Nascar were the last of the flatheads and the later wedge heads (SBC and all similar designs from the Big 3).

        Most racing and OHC street engines today use variations of the Cosworth DFV head design which provides better swirl and lower heat loss.

    • 0 avatar

      The Hemi was advanced enough to clobber its competitors of its day. It was also adaptable to 2 spark plugs per cylinder when modified for competition. They weren’t a very good street engine, however.

      Yes, the current use of the word is a cheap effort to capitalize on the legend.

  • avatar
    Big Al from Oz

    May he rest in peace.

    He was innovative. He saw the Porsche had a good idea using hemispherical combustion chambers and adapted that to a US V8 design.

    Very original.

    • 0 avatar

      Chrysler introduced their first hemi V8 in 1951. They developed it based on experience they had developing a WWII aviation engine. Tom Hoover adapted the old Chrysler hemi head design to the then-current big block in the ’60s. I have no idea why a man’s passing inspires you to make up history and spread ignorance.

      • 0 avatar
        Big Al from Oz

        It appears hemispherical combustion chamber were originally used in early artillery and had been adapted quickly into the automobile at the turn of the 20th Century.

        The hemispherical combustion chamber appears to be a European idea, created by the ever challenging goals of producing better weapons.

        The idea is military.

        FCA owning Chrysler seems to be almost like “two peas in pod”. FCA had this well before radial aircraft engines were ever made.

        Fiat was one of the first to use this technology.

        Hoover used existing technology and adapted it to the V8.

        The Fiat 130

        The project was entrusted to John Henry as the project manager who had previously worked as a co-designer on an earlier 100 horsepower racer in 1905. He developed the 130 HP while working with designer Giovanni Enrico and technical directors Guido Fornaca and Carlo Cavalli. The new design featured a chain drive transmission and a front-mounted 4-cylinder, 16,286 cc engine. The new engine incorporated multiple innovations for its time, including a bore greater than the stroke, overhead valves, hemispherical combustion chambers and centrally located spark plugs.

        The ignition for the 130 HP was provided by a Simms-Bosch magneto, while the power was controlled by a single carburetor. Despite the weight of more than 1000 kg (each piston had a weight of 4.5 kg) the wheels were still made of wood.

        • 0 avatar

          Hoover adapted existing Chrysler V8 hemi cylinder heads to a newer V8 short block. Nobody claims he’s the inventor of hemispherical heads, and he didn’t even create the ones used by Chrysler. He ran a development program that produced lots of successful competition engines. That’s cool in itself, and no reason for you to launch into your alternate reality world of misinformation.

          • 0 avatar
            Big Al from Oz

            I didn’t. You had made the “come back”.

            I originally thought that Ferdinand was one of the first to successfully adopt the hemispherical combustion chamber.

            But, I have found out otherwise.

            As for the Hemi Engine, it was a good engine for it’s time.

            I had not stated otherwise.

            Maybe you might have the issues, not I.

            You seem extremely sensitive to any comment regarding the US.

            To make you feel better the US is great country that had allowed itself to expand as it has.

            But, look outside of South Dakota. The world is an amazing place.

          • 0 avatar

            Is CJ from South Dakota? I’ve always read it as San Diego.

  • avatar

    RIP – this is why CHrysler was known as an “Engineering Company” for many years.

    Hemi, torqueflite, torsion bars, the unkillable Slant 6, unit body when the rest of the Big 3 were BOF…

    • 0 avatar

      I just wanted to say thanks for reminding me of something my late father used to say from time to time. I got to visit the Chrysler museum before it closed to the public and it very much reenforced that notion as well. Pretty much all the non-car exhibits were focused on engineering advancements.

  • avatar
    Ron B.

    Tom Hoover has been a type of Hero to me since I first heard of the Silver Bullet a very long time ago.

    I’ve owned a few non Chrysler Hemis, (Riley 15/6,Peugeot 404, Mercedes 280 with m110,several of those) But I have also raced a Chrysler Hemi on the Salt (see DLRA results for 1998)and I can vouch for the early Hemi’s ease of making huge power over the wedge I have also owned (426 Max wedge ,64 Fury ).
    I see a question regarding proof of the efficiency of hemi heads.While yes,it is a fact that hemi is not quite as thermodynamically efficient as today’s Pent roof chamber design with it’s four valves etc (another invention and design from the 1900’s) let us not forget that every week 1/4 mile records are being smashed with Hemi powered Dragsters,not wedge or Four valve engines but plain simple Chrysler derived Hemis. Over the Decades since the 1950’s many attempts at equalling the power made by Chryslers were made using Pontiac,Buick,Oldsmobile engines . Even some speciality designs with four overhead cams(sainty etc ) but none could produce the power needed to unseat the Hemi.
    There is your proof.

    • 0 avatar

      This ……

    • 0 avatar
      Big Al from Oz

      @Ron B,
      I do agree the good old Top Fueler Hemi’s are generating some awesome power.

      But, the reason for this is partly due to the politics of the NHRA with it’s very strict regulations on any opposing engine other than the Keith Black style Hemis entering into competition.

      The McGee engine was too successful against the Hemi’s on the dragstrip and were banished from competing in any sanctioned NHRA event.

      The Hemis current success is partly artificial as no other engine is allowed to compete against them.

      This is great for the progress of the sport. Not.

      Here’s a cut and paste and some links.

      “Australian brothers Phil and Chris McGee developed their own nitro racing engine. The pair dared to be different, coming up with the McGee Quad Overhead Cam design. The team began in the 1970s, redoing and refining the effort over the next 20 years until the the motor and others like it were banned from NHRA competition.”

      • 0 avatar

        So this isn’t about taking the U.S. down a peg and expressing your own nationalism, eh?

        To be honest, drag racing outside the U.S. doesn’t get the kind of attention here that other overseas motorsports do (eg. the Australian Touring Car Championship and the Bathurst events), but there are plenty of straight line speed fans in Europe, Australia and elsewhere.

        • 0 avatar
          Big Al from Oz


          I was involved in the drag racing scene back in the early 80s. Then turned my attention towards Rallying.

          We used to run an HQ van that pulled low 12s with BF Goodrich T/As, not drag rubber. The vehicle weighed 3 200lbs.

          My biggest bitch was diff centres. We ran a Salibury and want a Ford 9″. We became very good at rebuilding diffs.

          The original engine a 308 90 degree, bent 8 came out of a Pro Stocker of that era, a Torana.

          If you don’t know the Aussie GMH V8s were quite poor in performance. Much work was needed to get the engine up to that.

          At the time it was supposed to of been the quick Aussie NA registered van racing. This was a good effort.

          The Chevs, Hemi’s and Fords of the time were a better and cheaper option to develop as racing engines. This was due to the fact the US V8s were built in far larger numbers.

          I do like the Keith Black powered Top Fuelers and Funny Cars. I haven’t ever stated otherwise.

          I actually live about 3 miles from Willowbank. Google that and the WinterNats.

          I would say outside of NA, drag racing, speedway, etc Australia would draw it’s largest market.

          My first experience of motor racing was back in the late 70s when I used to go to the Speedway and watch the Sprint cars. Even back then as now it’s is the Aussie vs the US.

          I liked clay racing better than bitumen tracks. The clay and smell of the methanol stinging your eyes with the roar of the V8s. Great stuff.

          Maybe TTAC should come down under and experience all we have to offer with motor vehicles.

          If you haven’t noticed my comments that are viewed as pro or anti whatever, target the ones who can’t see the light outside of their own front door.

          Essentially if they put up a challenge and they are talking through their asses I will correct them, with fact.

          The US has done a great amount for the global vehicle industry. But, let’s be realistic about it’s actual impact has been.

          What I put forward isn’t a lie as I do research my comments. Yes, some of it can be construed as chest beating, but that is by the few on TTAC.

      • 0 avatar

        The McGee engine was NOT successful at all, they might have equaled the power output of the 426 based motors, but they never developed to the point they were remotely as reliable (A relative term in the nitro cars) as the hemi and NRHA banned it, and the other competing designs simply to try, unsuccessfully it turns out, to keep costs down, and to prevent a horsepower “race”. At roughly 10,000 HP, more power really isn’t needed, and everyone using the same basic parts does something to keep costs under control. No competitor to the 426 hemi replicas has ever really done well. A lot of it was simply due to most all them not having a decent block with replaceable cylinder liners and complexity of the valve train vs the Hemi’s 2 valve heads.

  • avatar

    Chrylser Australia did engineer the Hemi Six, however robust, it was not a true hemi.

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