Larger Gasoline Engine Option

[C/K Man]

No question the L8T 6.6L is a worthy successor to the L96 6.0L.  It is very close in output to the Ford 7.3L and seems to deliver better fuel economy.  Nonetheless for the last couple of years there has been persistent rumors that GM is considering an even larger gasoline V-8, possibly primarily for larger commercial trucks and other OEM's.  For the last 6 months or so the rumors have died down a bit, but recently something showed up on GM Powertrain's website that has me wondering.  What it is is a 454 cubic inch V-8 based on the LS family using the tall deck LSX high performance engine block.  Now before you say that engine is old news and is just a high performance (and expensive) crate engine, the engine I am talking about is a different one.  This one is a nearly completely dressed production engine that appears to use L96 intake, throttle body, and heads.  In fact, the extra row of head bolts on the LSX block are visible but not used as they would be with LSX style heads.  Defiantly a truck/commercial engine, and the website lists it as an 'OEM Test Unit' whatever that means.  Could this be the rumored larger gasoline V-8?:

 

      https://gmpowertrain.com/products/lsx-454-engine/

[XY74]

Premium fuel recommended, doesn't sound like something you would hear for a fleet truck engine.

[Pastusak.t]

3 hours ago, XY74 said:

Premium fuel recommended, doesn't sound like something you would hear for a fleet truck engine.

I was thinking the same thing. But I would love 500+ ft lbs on a gasser for towing. 

[C/K Man]

Yes, the compression ratio is high, but why the 6.0L sized truck intake manifold and throttle body?  The engine makes no sense unless it is built for some specific purpose.  The high compression ratio would be appropriate for CNG/LNG, but the stated fuel is gasoline.  And what does 'OEM Test Unit' mean?

[gearheadesw]

Would make a nice swap into my truck, just give me a computer with it so the tuning is done already.

[newdude]

10 hours ago, C/K Man said:

No question the L8T 6.6L is a worthy successor to the L96 6.0L.  It is very close in output to the Ford 7.3L and seems to deliver better fuel economy.  Nonetheless for the last couple of years there has been persistent rumors that GM is considering an even larger gasoline V-8, possibly primarily for larger commercial trucks and other OEM's.  For the last 6 months or so the rumors have died down a bit, but recently something showed up on GM Powertrain's website that has me wondering.  What it is is a 454 cubic inch V-8 based on the LS family using the tall deck LSX high performance engine block.  Now before you say that engine is old news and is just a high performance (and expensive) crate engine, the engine I am talking about is a different one.  This one is a nearly completely dressed production engine that appears to use L96 intake, throttle body, and heads.  In fact, the extra row of head bolts on the LSX block are visible but not used as they would be with LSX style heads.  Defiantly a truck/commercial engine, and the website lists it as an 'OEM Test Unit' whatever that means.  Could this be the rumored larger gasoline V-8?:

 

      https://gmpowertrain.com/products/lsx-454-engine/

 

 

You won't see this in the HD pickups as we've moved on to Gen 5 LT engines.  

[C/K Man]

7 hours ago, newdude said:

 

 

You won't see this in the HD pickups as we've moved on to Gen 5 LT engines.  

Agree.  Maybe in medium duty with a lower compression ratio.  Port injection is easier to convert to gaseous fuel, though there CNG conversions of LT 5.3L's.  I just wonder what the purpose of this LX 454 engine is.

[newdude]

32 minutes ago, C/K Man said:

 I just wonder what the purpose of this LX 454 engine is.

 

Hopefully to end up in my dream project LS swap 1988-98 truck lol.

[nick112288]

Those RPM ratings aren't much different than the 6.6 or Fords 7.3 so maybe there is hope......

[2020-2500]

I just wish someone would make a supercharger for the new 6.6 gas.  Seems like there is plenty of room for one.

[pokismoki]

On 1/6/2021 at 6:08 AM, 2020-2500 said:

I just wish someone would make a supercharger for the new 6.6 gas.  Seems like there is plenty of room for one.

6.2 supercharger parts wont fit ?  the ecm  is probably harder to tune or has more encryption which yet to be cracked