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Here’s A Look At The Cadillac LMC55.R V8 Engine

General Motors may be in the middle of transitioning to all-electric powertrains, but that doesn’t mean The General is done with internal combustion. Quite the contrary – in fact, GM’s ICE-based efforts extend all the way to France and the 24 Hours of Le Mans, where Cadillac managed to podium with the impressive LMC55.R cross-plane V8 engine. Now, we’re getting a closer look at the Cadillac LMC55.R V8 thanks to the following photos.

The LMC55.R cross-plane V8 engine in the Cadillac V-Series.R race car.

Recently making the rounds on social media, the photos present the Cadillac LMC55.R V8 both inside and outside the car, showing off the structure of the powerplant and a few of the technical details.

The LMC55.R V8 was designed and built by the team at the GM Racing and Performance Center in Pontiac, Michigan, and is the only hybrid naturally aspirated engine competing in both the WEC Hypercar class and IMSA GTP class. Contributions were also made by Roush Advanced Composites.

Making its debut in June of 2022, Cadillac’s LMC55.R V8 features 5.5 liters of displacement, dual overhead cams, 32 valves, and a 90-degree cylinder configuration. The engine also features “advanced materials and manufacturing techniques” (per Cadillac) that enable it to be mounted as a structural component in the Cadillac V-Series.R racing machine (also known as the Cadillac V-LMDh).

The LMC55.R V8 is also the only naturally aspirated engine in the IMSA GTP class. Peak power output is rated at 670 horsepower, while peak torque output is specific to the series in which the race car is competing.

Further details include dry sump lubrication, while output is routed through the Xtrac P1359 seven-speed sequential gearbox. The V8 is paired with a rear-mounted 50 kW electric motor. The Cadillac V-Series.R chassis is an LMP2-based cabon fiber monocoque, while vehicle weight tips the scales at 2,380 pounds.

Per a recent social post from Vince Tiaga, a team member at the GM Motorsports Competition Group, the decision was made to go with a naturally aspirated, cross-plane V8 as not only did it meet the team’s requirements, but it also “promised to deliver a distinctive sound that would make it easily identifiable as it roared around the track.”

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Jonathan is an automotive journalist based out of Southern California. He loves anything and everything on four wheels.

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Comments

  1. Can I have 1 to use in my Camaro.

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  2. They’ve already wasted billions on Omega and the Blackwing V8, what’s a few million more among friends stockholders? But I don’t think ICE will die as soon as they expect, so maybe some of this engineering will see production one day.

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    1. It did. This is the bones behind the LT6 in the Z06. This also explains the reason the LT6 is a flat plane DOHC as opposed to a blown small block. Most European and GT race classes have limits on what size and power adders an engine can have. Im not a fan of this engine nor the LT6. All that engineering yet a 5.3 vortec makes more torque below 4000 rpm.

      Reply
      1. The LT6 5.5 flatplane crank Z06 engine is a masterpiece and has been very successful for Corvette racing for 3 years now. The street version in the Z06 ironically is the same 670 horse like cadillacs race engine. The street version has been a great trouble free 8600 rpm redline engine.

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        1. Yes, great race engine, not as powerful as the LT5, or street friendly lacking low end torque, but a great race engine.

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    2. I don’t see my 23 blackwing as a waste. 668 hp and all the caddy comfort. I’m very happy with it.
      To each his own……

      Reply
      1. Remember you have a called Blackwing unless you have a CT6 Blackwing or detuned in a CT6 Platinum

        Reply
  3. Now that’s an ENGINE!! Screw electric. I’ll take it!!!

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  4. LOL, REMEMBER THE LAST TURD CADDILLAC BUILT? THE NORTH STAR….TOTAL GARBAGE.

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    1. Michael McQueen, just another troll. Your statement is not only patently false on every level, it reveals yourself as a person of very low IQ, any semblance of social cognizants, and who’s patents regret in the extreme not taking the abortion route….

      Reply
      1. cognizants –> cognizance
        who’s –> whose

        People in glass houses should dress in the basement. Your point is well made, but is still semi-literate.

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        1. Exactly Griz. -Kind of makes his/the point empty(de-valued) to me when the spelling and/or grammar doesn’t back it up. -Is it just ‘hasty pudding’?

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          1. I agree. Hasty texting….

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      2. Thanks for the corrections….

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    2. This is why people should keep their comments to themselves if you have nothing nice to say don’t say anything at all that’s what I was taught maybe other people should be teaching their children this and stay off social media sites it’s just causing a lot of trouble that we don’t need!
      Mind your business and stay out of other people’s business!
      Get off your phones and computers and get outside, get some sun do something positive!
      How about that?

      Reply
      1. I agree, but that’s a super run-on sentence.

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        1. Wow, yes, made mistakes in spelling and structure, but the message is clearly understandable. But focusing on these mistakes instead of the scum bag trashing my beloved Cadilac seems to tell me none of you [trashing my comment], are actually caddie fans…..

          Reply
    3. Get back into the right century……

      Reply
  5. Gen 6 small block hiding in plain sight!

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    1. This isnt the gen 6, nor a small block block for that matter. A small block is a 2 valve pushrod with 4.4 inch bore spacing.

      Also, this engine isnt any more technical than the current truch engines. The torque curve from the corvette shows its inferior to the 4.8 vortec below 3000 rpm, inferior to the 5.3 vortec and 4.3 LV3 below 4000 rpm.

      The 6th gen small block will be way more advanced than this, likely featuring an active thermal system, VVL feature and higher compression ratio.

      Reply
      1. STEVE, according to the team that developed the engine, this 5.5-liter DOHC V8 carries the small-block badge and the famous 4.400-inch bore spacing. This is a quote from an article discussing the LT6.Time will tell the lay out of the internals or configuration for for that matter, but there’s no denying dual overhead cams when it comes to timing advance and retard which is key for emissions. Either way I’ll be a fan.👀

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        1. As long as your not one of the people complaining that the 10 speed allison isnt an Allison, that small block “brand” is acceptable. Fact is this isnt a small engine. For displacing only 5.5L it’s barely lighter than the LT4/LT5. Its also much taller and lighter. The only thing small block about it is the 4.4 bore spacing. FYI, i dont consider the original LT1 DOHC a small block either. If it struggles to fit into any other car a small block came from, then I believe the correct term would be “big block.”

          If we’re being honest, the elephant in the room is European race requirements. Guess the Germans booed, cried, threw their sauerkraut and threatened WW3 over chevys dominance and thats why this car doesn’t feature the superior R07 engine (a carbureted 400 CI gen 2 small block that makes 850 HP and has a redline thats between 9-10000 RPM) makes the LT6 look like an asian performance wannabe.

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          1. “Taller and wider” curse you autocorrect, foiled again!

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          2. And it was actually the LT5, not original LT1 tgat was DOHC from the 90’s

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          3. The Lt6 weighs LESS than the Lt2. Where you get the “barely lighter than the Lt4/5. The main difference between big blocks and small blocks IS the bore spacing regardless of your incorrect opinion.

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    2. X-plane crank. Wonder if this is the ZR1 motor for the C8, rather than a TT LT6?

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      1. No John, the ZR1 engine will be the current Z06 5.5 liter flatplane crank engine with twin turbo’s

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  6. Thanks for the nice informative article on this latest V-8, I hope it gets put in the new Cadillac. I just put a new L9H 6.2l in my ’09 Hummer H2, its a nice engine too, runs great.

    Reply
  7. This is where we should be going, it doesn’t need to these power levels for a daily driver, but the cord just isn’t the answer to the next generation of automobiles. The ICE engine is nowhere as dirty as it once was and shouldn’t be the evil thing that it’s made out to be. Can’t believe more emphasis hasn’t been put on hybrid development.

    Reply
  8. I see a Caddy roadster on the horizon , something similar to the C8 Corvette. Ahhhh a nice SL class AMG, slayer.

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    1. Nah, the last gen 5.3 makes more torque in the “around town” engine speeds. Lookup motortrends deep dive of the LT6. It makes under 300 ftlbs of torque under 4000 rpm, or about the same as the 3.6V6, but weight almost as much as a 6.2 supercharged.

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      1. If they bring back skip-shift we should be good to go as we’ll need to keep RPM levels up. 🙂

        Reply
  9. The LMC55.R V8 sounds suspiciously like the C8 Z06 LT6.

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    1. thats because it is

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      1. Exactly! 90% the same. Some slight modifications. Also, understand that most GT races require that at least 500 units of each engine be built for production cars to keep pure F1 engines out.

        Reply
  10. I still miss the deep bass thunder of Corvette Racing’s pushrod V8s.

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    1. Coming soon. Corvette will get a 6th gen small block

      Reply
  11. New Z06 motor with electric motor attached, I want one

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    1. Coming, but long wait. Zora.

      Reply
  12. Drop this engine in a Celestiq to make a true “Standard of the World”!

    Reply
  13. CADILLAC cross plane Z06 flat plane.

    Reply
  14. All of this is really nice, but i doubt the dealerships will be able to (really) work on this engines. I’m scared to take my vette in with so many mistakes the dealers (tech”s) make. Not knocking the technicians but these engines are getting so complex that most dealers can’t work (not experiment, part to part) on them.

    Reply
  15. If Cadillac is going full electric I hope that they at least make a high performance v series hybrid before full sending it to electric imagine a ct5 starting like the race car I get it’ll be heavy but it’s just a thought

    Reply

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