By on December 27, 2016

2017 Chevrolet Corvette Grand-Sport overhead view (Image: General Motors)

It appears the Chevrolet Corvette is in line to receive a new dual-overhead cam V8.

An internal GM document detailing 2018 model year VIN codes was posted to the GM Inside News forum, and down on page five is buried treasure: “Passenger Car Engines for GMNA.”

The very last entry is a unicorn — the long rumored LT5 small block. General Motors lists the engine as “GAS 8 CYL, 6.2L, SIDI, DOHC, VVT, ALUM, GM” under code “Y”, which denotes the Corvette family.

In the past, there have been internal studies using DOHC heads on GM’s venerable small block architecture, but nothing came of it until now. On the surface, it would seem the big gain from adding overhead cams will be better breathing, as a DOHC setup allows GM more freedom when it comes to variable valve timing on both the intake and exhaust sides. The pushrod LT1 is limited to a set valve timing, as the single camshaft hits intake and exhaust at the exact same degree.

Where this will get interesting is in terms of packaging. How will GM manage to fit the larger DOHC heads under the Corvette’s low slung hood? Then again, the LT4-equipped Corvette Z06 does have a supercharger and two intercooler bricks tacked on top of the heads, so it might not be as tight a fit as imagined.

In other 6.2-liter V8 news, the supercharged LT4 is listed for A,Y, and K code cars. “A” denotes the Alpha platform (Camaro, CTS, ATS), Y means Corvette and K is the Omega platform that currently only underpins the CT6. It’s too early to proclaim that the CT6 will get a supercharged V8, but it is believed that Omega will find its way under other high-end GM products.

[Image: General Motors]

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77 Comments on “Pushrods, Be Gone: Corvette to Gain a DOHC V8 in 2018...”


  • avatar
    28-Cars-Later

    Great Fracking Scott!

    • 0 avatar
      stuki

      5 years ago, I’d quip sarcastically “yeah! since there’s such a dearth of DOHC sports/GTs put there…..”

      But now that those are all plugged up and dulled down with turbos, perhaps the ‘Vette can still retain a bit of an USP.

      The last great performance 8 I recall, was the AMG 63, which was a similarly sized DOHC. So there’s certainly potential….

  • avatar
    OldManPants

    Ooh! Look at its pretty eyes in the back with like raised eyelashes!

  • avatar
    JimZ

    Height of the engine with 4-valve heads is less important than its width.

  • avatar
    Pig_Iron

    What happened to “We don’t need no stinking overhead cams” we’ve heard since 1991? A quarter century later? Seriously? Sorry GM, you’re a day late and a dollar short. Unless this is a truck engine too, it’s dead in the water.

    • 0 avatar
      28-Cars-Later

      There are a whole swathe of truck buyers who chose GM because of the OHV setup, Ford or Toyota already had a fine DOHC offerings but the OHV set them apart. Traditionally (in the past 35 years), Corvette was the testing ground for a new corporate V8 so it seems RenCen is going full retard.

      So long GM, its been fun.

      • 0 avatar
        Adam Tonge

        There aren’t that many people buying GM trucks because of pushrod. It’s because they have very good engines. The average truck buyer doesn’t care about OHV, DOHC, whatever. That’s just BS for the internet. I’ve ordered dozens of trucks for fleet purchases. Never did I give a $hit about the OHV vs DOHC.

        • 0 avatar
          ajla

          “It’s because they have very good engines.”

          Luckily GM has a long history of excellent DOHC engines.

        • 0 avatar
          28-Cars-Later

          Excluding myself, I have known several people over the years who prefer OHV vs OHC and had made purchases as such.

          • 0 avatar
            Adam Tonge

            Some people care. The average buyer does not. Go to a construction site and survey truck owners. See if they even know the difference. And if they do prefer OHV V8s, is that because they don’t like ‘dem Fords? Would they switch to RAM if GM had a DOHC 6.2L V8 in the Silverado?

          • 0 avatar
            28-Cars-Later

            Younger hickish people I have encountered prefer F-150 (either the previous gen or EB if they can swing it) but they frequently bought GM or Dodge because of discounts, family connection (inc brand loyalty), or OTD pricing. Perhaps for them the OHC at the right price is still a buy, or perhaps they will shop FCA who will be able to undercut GM and still offer OHV (assuming FCA exists when this occurs). Older “GM” people (50+) like the OHV and for them I see used purchases because they are diehards.

          • 0 avatar
            Adam Tonge

            How are these GM customers that are afraid of OHC going to like a 10-speed transmission in their truck that was designed by Ford?

          • 0 avatar
            28-Cars-Later

            The older people I don’t think will be buying new when this occurs, but those with a Ford bias will not be happy I imagine with those facts. I think sub-40 is not as adverse but for them price will be a serious consideration (economic depression and all). I suspect GM thinks the same, hence the asshattery, but I think long term this hurts GM rather than helping in a meaningful way. Since cost is such a serious consideration it is wiser to run your reliable, depreciated, product which allows for more wiggle room in margin to remain competitive. Building whole new drivetrains is a large expense which one will want to recoup quickly, yet by the time this debuts Ford EB will probably be paid for and Dodge will continue running 2009 product because Chrysler needs to keep the lights on and thus both can undercut GM. RenCen should have learned from its $12B Cadillac misinvestment vs Ford’s $1B Lincoln. This is not the time for drastic product changes, this is the time for small investments to remain relevant but also to stay competitive.

          • 0 avatar
            Adam Tonge

            I don’t think they should stop with the evolution of the pushrod V8, but I’m not afraid of OHC either. That being said, I don’t think GM can make a V8 engine that is better in a truck than their current crop of V8s. If I owned an F150, the only thing that I would covet from other truck manufacturers is the mighty 6.2L GM monster.

          • 0 avatar
            JimZ

            I think you’re going way too far into assuming everyone else cares about the same things you do.

          • 0 avatar
            28-Cars-Later

            @bball

            Unless this becomes some kind of one off Corvette thing, which it certainly could be, it signals the end of LS development IMO. I don’t see new GM developing multiple V8 engine families moving forward, especially since the V8 is evil per ManBearPig and all.

            @Jim

            The beauty of a message-board is you are only judged on what you do or do not say, and your posts say so much.

          • 0 avatar
            Adam Tonge

            I think they are going to have to develop multiple V8 engines, or at least have two families that share parts. Cadillac/Corvette is getting a OHC V8 it seems. I can’t see GM putting that engine in trucks. Johan wouldn’t stand for that.

          • 0 avatar
            28-Cars-Later

            Perhaps my “shaping Northstar into a model” comment let on more than I knew at the time.

            “Cadillac/Corvette is getting a OHC V8 it seems.”

            Perhaps, but I cannot see how this makes fiscal sense especially when there is already an existing award winning engine family in the corporation. I can’t imagine Ford saying, yes we will continue the Mod motor but we will also develop an entirely different V8 to be used in three or four models.

          • 0 avatar
            JimZ

            “I can’t imagine Ford saying, yes we will continue the Mod motor but we will also develop an entirely different V8 to be used in three or four models.”

            They did that, didn’t they? The 6.2 SOHC in the Super Duty is an entirely unique engine. what’s more is they still offer the 6.8 V10 along side it in the chassis cabs.

          • 0 avatar
            28-Cars-Later

            The V10 is a Mod motor but you’re correct on the Ford 6.2:

            https://en.wikipedia.org/wiki/Ford_Boss_engine

        • 0 avatar
          Adam Tonge

          It’s very possible that they screw it up. If I were GM, I wouldn’t want to eliminate the push rod V8s because they are some of the best engines period. GM has done well making them better over time.

        • 0 avatar
          Lou_BC

          I have to agree with Adam. Stalwarts will cite pushrods as a reason to buy but that is just fanboy logic. Harley Davidson fanboys are a prime example. Ironically, the fastest bike in the Harley lineup has a 4 valve overhead cam engine. It makes perfect sense for an overhead cam V8 to be in the Corvette. You won’t see RPM numbers like the Boss 302 or GT350 Mustangs with pushrods.

          • 0 avatar
            golden2husky

            No, you won’t see those RPM numbers, but frankly I don’t miss the extra revs. The LT motors ooze power effortlessly. The sound and power at 6,000 rpms is amazing. IMHO they give up nothing in trade for more compact packaging, simplicity, and lower cost. The fact that pushrods have been around forever is only a marketing handicap, not a real one.

          • 0 avatar
            MichaelH9

            Well said Lou

    • 0 avatar
      LS1Fan

      Market perception is what happened.

      GM needs to take the Corvette upmarket into the GTR /Ferrari entry exotic market space. Good luck selling a pushrod valvetrain car in that market space.

      • 0 avatar
        28-Cars-Later

        I had to roll my eyes at this, not because of you, but because of the notion of a Corvette being in Ferrari “market space”. GM failed hard and it should have been liquidated, but in a span of only a few years -with the same toxic corporate culture- it thinks it can compete in Ferrari territory? This is the same asinine thinking which gave us JdN, Pen Boy, and CT Melody Lee. Hows Cadi-lack doing again? C7 sold 27,327 units in MY16, I guess they are shooting for the CT6 level of sales for a future Corvette. GM once you give up the current market position for Corvette, it will be replaced by Mustang (or something similar from Ford), and you will never regain it.

        • 0 avatar
          doctorv8

          “GM once you give up the current market position for Corvette, it will be replaced by Mustang (or something similar from Ford), and you will never regain it.”

          Well, don’t forget that the new Camaro, esp the ZL1, virtually matches C7 performance in nearly all measures except road course lap times, and the new Z28 will probably generate near Z07 lap times.

          So they have that market position somewhat well covered, and I bet Camaro would make up some sales ground on the Mustang if there is no longer a $55k Vette in the picture.

          • 0 avatar
            28-Cars-Later

            You may indeed be correct sir, but here is what I think is happening in this regard. You have a 55K Corvette C7 and a 61K Camaro ZL1, if the Corvette is removed in theory the 61K ZL1 would see a sales increase however you also may be giving up the unit profit per model of Corvette vs Camaro which may in fact cost more to build. You combine this with all of the complaints about the Camaro which the Mustang does better (fit & finish, visibility, ergonomics, interior room) and “removing” Corvette from the fray may actually hurt GM financially more than it helps. One would have to do his research, but does a 55K C7 buyer want to spend $100K on his next Corvette, and if not, will he just default into a new Camaro?

          • 0 avatar
            Lou_BC

            @28-Cars-Later – I don’t think there are many Corvette buyers cross-shopping Camaro’s therefore I believe that you are correct.
            The Corvette has always been GM’s flagship car. Unlike the Camaro, it has never ceased production. It also shouldn’t be aimed at the Euro-Supercar demographic. That market is determined by reputation and prestige. You don’t automatically gain bragging rights by saying, “I own a Corvette.” Cadillac is a prime example of what happens when you try to fight above your weight class.

          • 0 avatar
            golden2husky

            I don’t agree that the Camaro will be a viable substitute for the Corvette. Should GM go with the much-rumored mid engine platform and the market necessitated DOHC engine, the typical buyer will be priced out of the market. I did not have an issue with shelling out $82K for my C7, but a $150K for a mid engine model would have me looking at another car and that car would not be a Camaro. I’d say that most Corvette buyers would agree. It should also be noted that the cheaper Vettes with 1LT trim levels are not the meat of the Vette market.

            While I think a performance flagship that slots over the present Corvette would be awesome, I’m not sure the business case works.

          • 0 avatar
            28-Cars-Later

            All good points, gentleman.

          • 0 avatar
            Lou_BC

            golden2husky – agreed. If the Corvette moves into that 150k price range it puts it up against a whole new class of vehicles and alienates the core high end Corvette buyer.

    • 0 avatar
      TheDoctorIsOut

      Assuming the alleged mid-engine prototype and concomitant Car and Driver predictions are true it would make sense if there’s to be to a world-class mid-engine Corvette they’re going to have to have something more than yet another rehashed OHV small block to put into it, torque numbers or low-profile notwithstanding. Considering the oxygen in the press that Ford and their Ford GT has gotten from their EcoBoost V-6, Chevy’s going to need something more than another LS- variation just to be on the same page as them.

    • 0 avatar
      raph

      A mid-engine vette will do fine with a low volume V8, Ford does fne with the 5.2 in the GT350 and they only sell about 5k units a year give or take.

      GM has hit a wall with the 2 valve cam in block V8. Notice something you don’t see in GM’s stable? LS and LT engines that are making 100 hp/l or better in naturally aspirated trim.

      GM’s V8s can certainly make that kind of power naturally aspirated but they can’t do it for long and certainly not long enough to satisfy even future Herr Trump’s sissy EPA (which will in all likelihood mandate coal-rolling as a mandatory function even on gasoline engines).

      Enter a DOHC VVT 4v 6.2L V8 easily capable of making that number (and certainly >>specifically<< beating Ford for the domestic V8 specific output game while claiming otherwise – GM is entirely predictable like that).

      GM's pushrod engines are great. They make great power where Americans like it most and get great fuel economy and they are compact, cheap and easy to work on and modify but the basic engine configuration necessarily relies on increasingly larger displacements to make up for the valvetrain limitations that a 2 valve pushrod engine imposes since they suffer in the low and mid lift flow regions.

      A good 2 valve head can match or exceed the airflow of a 4 valve head at high lift but to make up the low and mid lift deficiency more aggressive cam timing is required as well as cam lift which further stresses an already highly stressed valvetrain configuration requiring exotic materials (titanium valves for example which isn't most friendly material since it likes to microweld IIRC requiring coatings which will eventually wear and have to be handled with kid gloves since knicks will propagate into cracks. Not to mention the cost over more sturdy and more mundane materials) to compensate.

      In addition there architecture limitations that make steadily increasing displacement less attractive as well not only from a longevity standpoint but it gets harder to offer an engine that doesn't gain a reputation for being a bit of a glass jaw when serious power is thrown at it (something you don't see in the C6 LS7 Z06 world too often is a stock block 1000 horsepower engine build where Chrysler and Ford engines as well as smaller displacement GM engines are able to do on a stock block).

      By way of example (and forget about the flat-plane-crank since it's more marketing than anything else and has practically nothing to do with the Shelby's 5.2 revving to 8200 rpm) The Voodoo V8 in the Shelby can rev well past its factory RPM limit by at least another 400-600 rpm without compromising valvetrain stability (people have successfully revved them to 9000 rpm on all stock hardware) and the cams generally use about 30-40% less lift with a much more gentle camshaft profile. Yet the engine makes good usable power over a wide RPM range.

      To use the same sort of cam in GM's pushrod 2 valve V8 would make you think it was 1987 all over again.

      A mid-engine vette certainly eases the design constraints normally imposed when trying to fit a DOHC 4v V8 in a narrow set of chassis rails (figuratively speaking) since there is more space in the rear to work with (no passenger space to intrude upon is one and the track tends to be wider as well) ignoring the benefits of a DOHC 4v arrangement becomes silly nitpicking by the pushrod crowd. Also the CG on the engine doesn't take that big of a hit and the engine can certainly come within 50 pounds or less weight when compared to its LT stablemate which GM can certainly compensate elsewhere and it will certainly be less than the combined weight required to mount and keep properly cooled a comparably powered supercharged pushrod V8.

      In short it's a good fit for a mid-engine Corvette that provides exclusivity for what will surely be an expensive car and will probably break new ground when it comes to V8 engine refinement at GM.

      • 0 avatar
        Lou_BC

        raph -Agreed. A flat plane crank doesn’t have a great affect on how high it will rev but has great affect on how quick it will rev. For example:Yamaha went to a cross plane crank to smooth out the deliver of power in their 1000 cc R1 sport bike.

      • 0 avatar
        Noble713

        “GM has hit a wall with the 2 valve cam in block V8. Notice something you don’t see in GM’s stable? LS and LT engines that are making 100 hp/l or better in naturally aspirated trim.”

        Is hp/L really the performance metric they should be chasing, though?

        What about hp / kg engine weight? hp / cm3 of total engine volume? By either of these metrics the OHV engines blow the competition away, and IMO these are more significant considerations when taking a holistic approach to vehicle engineering. If GM can’t communicate the dominating advantages of the OHV architecture to prospective buyers, that’s a marketing issue, not an engineering one.

        http://gmauthority.com/blog/2014/02/corvette-racings-competition-complains-about-its-pushrod-engine-design/

        • 0 avatar
          pragmatic

          Absolutely. Power per cubic inch engine displacement is a meaningless number. Power per cubic inch outside volume, power per pound engine weight or even power per dollar engine cost are the only metrics that should matter on a production vehicle. By these measures the CSB is a winner

    • 0 avatar
      MichaelH9

      @golden2husky

      OHV engines don’t necessarily make torque quicker. Compare the torque charts of the Toyota DOHC 5.7L vs the OHC 5.7L HEMI V8 you will see the Toyota engines makes more torque at lower RPMs.

      OHC engines run cooler and are have the ability to be more efficient because the greater variability of the valve timing. That’s obviously something GM realizes.

      Also OHV engines don’t intrinsically sound better either, the sound of an engine rests more on how the manufacture engineers it to sound. A good example is the Viper OHV V10 engine of which the sound is often a complaint vs the Porsche Carrera GT DOHC V10 sound was very much praised by the auto media.

      There may be a lot of misinformation about the inferiority of OHV engines, but there’s also an equal amount for the advantages of it.

  • avatar

    DOHC for the Corvette. Finally the Eighties have arrived for GM’s pride.

  • avatar
    ajla

    Important things:
    1. Still a V8
    2. Still over 4.0L displacement
    3. Still no turbos
    4. The document shows the 6.2L pushrod V8 continuing in the “Y” car so the DOHC V8 is likely just for the top shelf Corvette a la C4 ZR1.

  • avatar
    KevinB

    About. Damn. Time.

    • 0 avatar
      28-Cars-Later

      Because Northstar was such a resounding success.

      • 0 avatar
        Adam Tonge

        “We should never try things because they didn’t work decades ago”

        -28CL-

        • 0 avatar
          28-Cars-Later

          Quad-4
          Northstar
          Shortstar
          2.0 LT2
          3.4 LQ1
          3.6 LY7 & LLT

          GM doesn’t do OHC well. Assuming they even can, the initial motors won’t be up to par with everyone else in the field. Why am I buying GM again?

          • 0 avatar
            JimZ

            Ok, so can you point out how any of those engine’s issues are *because* they were OHC?
            ‘cos GM’s had plenty of pushrod stinkers too (e.g. HT4100.) Blaming that list of engine’s various shortcomings on where the camshafts are located reeks of Internet Car Guy blather. I mean, the main flaw of the Quad 4 was the lack of balance shafts on a large-displacement 4 cylinder; whether the cams are in the block or head had nothing to do with that.

          • 0 avatar
            ajla

            The LQ1’s issues were because it was OHC.

            You could make the argument on the timing chain for the LY7 and LLT as well.

          • 0 avatar
            Adam Tonge

            (raises hand)

            I kind of liked the Qaud 4

          • 0 avatar
            28-Cars-Later

            4100 was rushed after failures of the Olds Diesel and 6.0 368, it was never intended to power RWD product and should have never been used. The motor was eventually “fixed” around MY87 and was reintroduced as the 4.5 which was an excellent motor despite the odd iron head/alum block setup.

            Quad-4 was Oldsmobile’s last developed engine and had many years of development and financial resource behind it. Despite this, it had several problems in an era where it could not afford any.

            http://www.auto-facts.org/Quad-4-problems.html

            Then there was the LQ1:

            “GM literally took a pushrod engine [(the 60V6)] and put two gigantic OHC heads on it. I’m sure they changed a few things but not much. Its a very cool idea and the result was impressive dynamically, but the 3800 could perform just as well and was more reliable. It also made more torque at a lower RPM. It was a really big hassle for GM to be able to say “Our cars are OHC! Please don’t buy an Accord!”.

            http://www.gminsidenews.com/forums/f19/terrible-3-4l-dohc-engine-42870/index7.html

            Then the LY7 with timechain issues in this millennium.

            https://community.cartalk.com/t/gm-customer-satisfaction-program-recall-of-3-6l-v6-engine/62806

            http://www.cadillacforums.com/forums/cadillac-forum/t-783586.html

            Go ahead and buy OHC GM, best of luck.

  • avatar

    Great!

    Finally GM will have an answer for all those customers who had been put off from buying a ‘Vette because of its ancient, well-proven valvegear.

  • avatar
    Featherston

    “In the past, there have been internal studies using DOHC heads on GM’s venerable small block architecture, but nothing came of it until now.” Did the LT5 never happen? Yes, that was a joint GM-Lotus-Mercury Marine project, but it seems to me that that engine did in fact reach the buying public.

    “The pushrod LT1 is limited to a set valve timing….” Lift and duration–I think–are fixed, but cam phasing is not. Broadly speaking, this constitutes VVT, or at least a type of VVT.

    Signed,
    That Guy

    • 0 avatar
      JimZ

      the LT5 wasn’t really part of the GM “small block” architecture, it was basically a completely distinct engine.

      • 0 avatar
        Featherston

        Well now you’re just inviting the thread to fall into a black hole of That Guy-itude, JimZ. As if I hadn’t. :-)

        Aren’t the LS and later engines distinct from the SBC as well? The point was that GM *has* done a production DOHC V8. Or at least the Greater GM Co-Prosperity Sphere has, albeit on a limited basis.

  • avatar
    dal20402

    Admission that the current LT1 has taken the OHV 2-valve architecture as far as it can possibly go?

    Or perhaps a wish to have a V8 that’s suitable for use in luxury cars. The last couple generations of pushrod V8s haven’t been ideal from a NVH perspective, and maybe a DOHC engine can be a bit more civilized at the same power level.

    • 0 avatar
      JimZ

      what does the valvetrain configuration have to do with NVH?

      • 0 avatar
        dal20402

        It shouldn’t, but the NVH results from the current OHV engines aren’t good. That makes me think GM had to optimize for other goals at the expense of NVH. Lots of OHC engines make similar power for displacement without the same issue, although they tend to be bigger and heavier.

        • 0 avatar
          JimZ

          well they also went DI, and the HPFP on DI engines can be a major source of noise.

          • 0 avatar
            golden2husky

            The DI sounds are not perceptible, at least not from in the car. However, the LT engines do have some shake at idle. Perfectly acceptable, desirable even for the Vette and Camaro. Not acceptable for a luxury application.

  • avatar
    carguy

    Let me get this straight: So GM releases a high performance, naturally aspirated, large displacement, quad cam V8 engine and some “purists” complain?

    If you have ever wondered how automotive forums got their bad name, this may be Exhibit A.

    • 0 avatar
      28-Cars-Later

      When will you be putting your deposit down?

    • 0 avatar
      raph

      Of course they would, it makes all that chest beating hollow when GM’s top car goes with something they consider anathema and forces people to realize the 2 valve pushrod V8 is approaching a wall. The LS7 in the C6 Corvette was about as far as you could go with a production pushrod V8 in terms of overall performance, the LT engines are a refinement on the LS engines but really don’t offer the capability to significantly push those boundaries.

      Even if GM were to go back to a 7 liter V8 a comparable 6.2 liter V8 could easily put 50 or 60 horsepower on that 7 liter in production trim with better durability and NVH.

      People have made 700+ horsepower with GM’s big V8’s naturally aspirated but they certainly don’t meet company durability or NVH requirements nor emissions requirements.

  • avatar
    skor

    I once bought a low mileage, super clean, Cadillac Seville that ran well for years for $1,500. How was that possible? It was the last model year with the 4.9 engine…… totally uninspiring, middling, little mill that just ran. By the time I bought that push-rod motor equipped Caddy, the 4.6 OHC engines were detonating with the frequency of Appalachian meth labs. The death stench of GM’s “Northstar System” stank up everything Cadillac and the prices for anything Cadillac plummeted faster than Nina Hartley’s panties.

  • avatar
    pragmatic

    I think this is a mistake. While I know the advantages of DOHC I’m not a fan of the design when applied to V or even opposed engines for that matter. DOHC just adds too much width and/or height. A light weight OHV with the cam in the V is the way to go. Make up for the lack of top end power by making it larger displacement. The large displacement V type engine with push-rods is lighter, smaller, less complex and more fuel efficient than a similarly powerful NA DOHC engine. Yes the Ford DOHC 5.2 liter make a little more power (66 more hp) but less torque (36 less) than the 7 liter from Chevy. The Chevy gets better fuel economy, has a smaller, lighter engine that is packaged lower in the chassis. All of this at a much lower manufacturing cost.

    • 0 avatar
      raph

      And that matters why on a Corvette that has the engine in the back and will be the range topping performance car in GM’s lineup?

      They can still achieve good fuel economy with a large displacement DOHC V8, weight won’t be that much different (it will certainly be lighter compared to a supercharged V8 and the CG on the engine will either be a wash or better since the heads aren’t the equivalent of sticking a 60 pound box of aluminum on top of the engine). The width of the engine won’t matter since there will be way more space behind the passenger cell (unless GM decides to go backward in time and designs a car with a rear track purposefully narrower than the front and/or wants a lot of empty space useful for fitted luggage I guess in the gunwales).

      Ford’s Coyote V8’s are about 3 inches wider and depending on the application no taller than some of GM’s V8 truck engines and is within 40 pounds of the LS engine (could be more now since the LT is supposedly lighter but the 5.2 is lighter compared to the Coyote so the delta in weight is more than likely about the same if not narrower).

      Everything you cite matters if GM wasn’t working on a mid-engine Corvette and is blown to hell when you look at its top offering currently that has to use a supercharger to make serious power since the weight of the supercharger and its heat exchanger are stacked over the top of the engine (a DOHC cam V8 offers more valley space so it can package a supercharger better if need be).

    • 0 avatar
      MichaelH9

      Pretty much that entire statement is not true at all.

      Where is your proof that the 7L LS is lighter than the 5.2L Voodoo? Ford hasn’t released any weight figures for the engine and they actually did a lot of engineering work on lightweighting the engine. Sure a OHV engine might be lighter PER the SAME engine size, but where talking a 1.8 liter increase in size here. That means 7.0L will have more metal in the block as well as a larger physical size of the block.

      You’re also dead wrong about the Camaro 7 liter being more fuel efficient. The Camaro Zl1 (7.0) was rated at 13 city 19 hwy 15 combined, the Mustang GT350 (5.2) is rated at 14 city 21 hwy 16 combined.

      Hp is far more important than torque in a performance car application. Especially 66 more hp vs a mere 36 lb ft defect. The FPC 5.2 also revs MUCH quicker so you get more usable power quicker and has a far more invigorating howl.

      • 0 avatar
        pragmatic

        Voodoo weights 13 pound less than the Coyote V8 (Wards Auto January 2016 quoting Ford Engineering Dept) Ford lists the weight of the Gen 2 Coyote as 445 lbs (not sure if this is fully dressed) so

        Voodoo is 432 lbs making 526 hp and 429 ft-lbs 14/21 mpg (all from Wards)
        LS7.0 is 454 lbs making 505 hp and 481 ft-lbs 13/19 (Camaro) 15/24 (Corvette)(all from GM PR)

        I’d call all those equal. The Voodoo is more expensive, shorter (4 inches) and wider (4 inches)

  • avatar
    dukeisduke

    Everything old is new again. Only this time, the engines won’t be assembled in Stillwater, Oklahoma, but likely in Wixom, Michigan.

    Here’s a very good post-mortem of the original ZR-1, from the September, 1995 issue of Car and Driver:

    http://www.caranddriver.com/features/chevrolet-corvette-zr-1

  • avatar
    drewtam

    No comment yet about the “SIDI” acronym (spark ignited direct injection)?

    Switching to direct injection is also a pretty big head rework, and can increase the height of the engine.

  • avatar
    Fordson

    Coming to this late, but I’m really surprised that no one has pointed out yet that one reason GM is hitting a wall with the 2-valve OHV is that the cylinder deactivation system they use in these engines doesn’t like to rev beyond 6500 rpm…that’s the reason that the LS7 is going the way of the dodo…it made 505 hp, but it did it by revving to 7k rpm…since you are not going to make EPA highway mileage targets in an over-6-liter engine without cylinder shutdown, all other current and future SBC versions have to have it. And since you’re not going to make mid-400 hp with a 2-valve, OHV N/A engine smaller than 6 or so liters in size…that’s how big it has to be.

    Everyone is really happy that the current 6.2L versions make 460-465 hp, but not so happy that at the 6500 rpm at which that power level is reached, there is a rock-hard fuel cutoff. They could make over 500 hp with these new engines if they could rev to 7k, what with the VVT that they have now, but the way they had to incorporate cylinder deactivation, revving to 7k does not meet their longevity and durability targets.

    it’s a heck of a lot easier to implement cylinder deactivation when you have separate cams for each bank, and easier yet when you have separate cams for intake and exhaust.

    So they limit them to 6500 and use forced induction to get to the power levels they need.

  • avatar
    Detroit-Iron

    To paraphrase Dr. Ian Malcolm “your engineers were so preoccupied with whether or not they could that they didn’t stop to think if they should. “


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