[FenwickHockey65]

Apparently an 8+ liter gasoline V8 is in the works for future GM/Navistar commercial trucks.

[NW-99SS]

Originally Posted by FenwickHockey65

Apparently an 8+ liter gasoline V8 is in the works for future GM/Navistar commercial trucks.

That will take LS/LT factory displacement to a whole new level! I suppose Ford's 7.3 gasser has some influence, but I am surprised to see them going to that extent after announcing the 6.6 and using the 6.0 for over 15 years.

[DGthe3]

Originally Posted by FenwickHockey65

Apparently an 8+ liter gasoline V8 is in the works for future GM/Navistar commercial trucks.

Which would be in the 500ish cubic inch range

Originally Posted by NW-99SS

That will take LS/LT factory displacement to a whole new level! I suppose Ford's 7.3 gasser has some influence, but I am surprised to see them going to that extent after announcing the 6.6 and using the 6.0 for over 15 years.

Yeah, it is a surprise. But if its going to be for the medium duty (4500/5500/etc) type trucks I can see a case for it.

[Martinjlm]

Originally Posted by NW-99SS

That will take LS/LT factory displacement to a whole new level! I suppose Ford's 7.3 gasser has some influence, but I am surprised to see them going to that extent after announcing the 6.6 and using the 6.0 for over 15 years.

I would be very surprised if it is done off the small block. The 7.0 was about as far as anyone dared stretch the small block. There used to be an 8.1L big block V8 for Medium Duty back in the late 80s early 90s. I would expect a modernized version of something like that.

[DGthe3]

Originally Posted by Martinjlm

I would be very surprised if it is done off the small block. The 7.0 was about as far as anyone dared stretch the small block. There used to be an 8.1L big block V8 for Medium Duty back in the late 80s early 90s. I would expect a modernized version of something like that.

Good point. The special tall-deck LSX block maxes out at 454 cubes I think (7.4L). But given all that they had to do to hit those kinds of numbers, I don't see how GM could go with small block architecture for an 8L plus heavy/medium duty truck engines. Maybe if they did a small block based V10 ... but that would probably be more work than just doing a new big block V8 line.

[NW-99SS]

Originally Posted by Martinjlm

I would be very surprised if it is done off the small block. The 7.0 was about as far as anyone dared stretch the small block. There used to be an 8.1L big block V8 for Medium Duty back in the late 80s early 90s. I would expect a modernized version of something like that.

Another "modernized" BBC...that would be surprising. The LSx 454 already has the tall deck block capable of over 500 cubes. I would be much more surprised to see another "new" BBC from GM, than a big bore LS/LT.

[lbls1]

^Didn't GM halt production of their big block motors altogether? I could understand if an extreme duty, off road vehicle would require an engine at that size and torque, but my understanding was that GM was doing just fine with their 6 liter duramax motors for high torque applications. I would love to see the big motors made again, but with the state of the automotive industry (even with CAFE and fuel requirements in limbo) I highly doubt that there are plans to manufacture large and inefficient engines.

[NW-99SS]

Originally Posted by lbls1

^Didn't GM halt production of their big block motors altogether? I could understand if an extreme duty, off road vehicle would require an engine at that size and torque, but my understanding was that GM was doing just fine with their 6 liter duramax motors for high torque applications. I would love to see the big motors made again, but with the state of the automotive industry (even with CAFE and fuel requirements in limbo) I highly doubt that there are plans to manufacture large and inefficient engines.

So the 8.1 BBC based Vortec has been dead since 2010.

https://www.hotrod.com/articles/gm-v...n-big-brother/

No way will a Vortec/BBC meet today's emissions standards.

6.0L was a great engine, but terrible on fuel. Hoping the new 6.6L gasser does better, even though I would never own an HD truck without the 6.6L Duramax diesel.

[DGthe3]

Originally Posted by lbls1

^Didn't GM halt production of their big block motors altogether? I could understand if an extreme duty, off road vehicle would require an engine at that size and torque, but my understanding was that GM was doing just fine with their 6 liter duramax motors for high torque applications. I would love to see the big motors made again, but with the state of the automotive industry (even with CAFE and fuel requirements in limbo) I highly doubt that there are plans to manufacture large and inefficient engines.

I'm 99% sure that all trucks over 8500 lb (10,000 for vans & SUVs) gross vehicle weight rating (curb weight + payload) are exempt from CAFE . So basically anything bigger than a half ton doesn't contribute to an automakers CAFE score. I think it has something to do with vehicles of that size being considered commercial rather than passenger vehicles.

[Martinjlm]

Originally Posted by lbls1

^Didn't GM halt production of their big block motors altogether? I could understand if an extreme duty, off road vehicle would require an engine at that size and torque, but my understanding was that GM was doing just fine with their 6 liter duramax motors for high torque applications. I would love to see the big motors made again, but with the state of the automotive industry (even with CAFE and fuel requirements in limbo) I highly doubt that there are plans to manufacture large and inefficient engines.

Ironically, it was one of the first two or three “end of production” programs I led in my first middle management job. As Manager - Engine Service Operations, one of my assignments was to take old programs out of production while maintaining capability for customers to get service parts. My first three programs were the Big Block V8s (7.4L / 8.1L / 8.2L), the original 4.3L V6, and the THM400 transmission. I just don’t remember what order they were in.

Fun Fact: The Chief Engineer for the Big Block engine when I took it out of production was Bill Large. At the same time I was working with a guy named Bruce Bruce and a buyer whose name was Les Purchas. I can’t make that stuff up.

[lbls1]

^I'll stay tuned then. Not everyday we actually get someone directly involved in the mfg. of the cars/trucks/products. Very good to know.

[lbls1]

Originally Posted by DGthe3

I'm 99% sure that all trucks over 8500 lb (10,000 for vans & SUVs) gross vehicle weight rating (curb weight + payload) are exempt from CAFE . So basically anything bigger than a half ton doesn't contribute to an automakers CAFE score. I think it has something to do with vehicles of that size being considered commercial rather than passenger vehicles.

Good to know. I wasn't sure.

[lbls1]

Originally Posted by FenwickHockey65

GM-trucks.com posted up a rumor in reference to an LT4 powered Silverado SS.

Keyword rumor.

I just stumbled onto this. That would bring a lot of excitement to the brand.

But (apologizing for my honesty) they must do something with the design. The Silverado is a nightmare. It needs some consolidation at the front clip. The body and side profiles actually are good. I would spring for a 460hp LT4 or vortex twin cab Silvie (uh boy....here we go again....).

[NW-99SS]

Originally Posted by lbls1

I just stumbled onto this. That would bring a lot of excitement to the brand.

But (apologizing for my honesty) they must do something with the design. The Silverado is a nightmare. It needs some consolidation at the front clip. The body and side profiles actually are good. I would spring for a 460hp LT4 or vortex twin cab Silvie (uh boy....here we go again....).

460 LT4? You can get an 18 or 19 6.2L with 420hp already. 40hp is easy to add to these truck 6.2s.