Jump to content

L8P crate engine. L8T + LT2 cam = monster gain.

Epsilon Plus
 Share

Recommended Posts

Epsilon Plus Enthusiast

Epsilon Plus

Posted
Posted

Just saw this today. Apparently at the end of last year GM Performance dropped an L8P crate engine. Looks to be just a cam (and likely valve springs) only L8T. Same intake/exhaust manifolds, compression...etc. It really showcases the monster potential of one of GMs greatest engines. Cam only and jumping from 87 to 91 it bumps from 401/464 to 523/543. That's a monster gain of 122hp and 79tq from a moderate cam size (relative to "big" aftermarket cams of 240+ duration and .600+ lift).

 

Cam is from an LT2 P/N: 12736191 other part number change on the crate engine is the cylinder heads but that's very likely only the stronger valve springs to support the increased ~.50 lift. Duration increases from 193/199 to 218/231. That exhaust duration should make the truck THUMP at idle through the big 3.5" exhaust.

 

Impressive. Most impressive.

 

https://www.chevrolet.com/performance-parts/crate-engines/l8p

  • Like 2
bruceb58 Enthusiast

bruceb58

Posted
Posted

I wonder what the specs for HP/Torque vs RPM between the two.

Pryme Senior Enthusiast

Pryme

Posted
Posted
10 hours ago, Epsilon Plus said:

Just saw this today. Apparently at the end of last year GM Performance dropped an L8P crate engine. Looks to be just a cam (and likely valve springs) only L8T. Same intake/exhaust manifolds, compression...etc. It really showcases the monster potential of one of GMs greatest engines. Cam only and jumping from 87 to 91 it bumps from 401/464 to 523/543. That's a monster gain of 122hp and 79tq from a moderate cam size (relative to "big" aftermarket cams of 240+ duration and .600+ lift).

 

Cam is from an LT2 P/N: 12736191 other part number change on the crate engine is the cylinder heads but that's very likely only the stronger valve springs to support the increased ~.50 lift. Duration increases from 193/199 to 218/231. That exhaust duration should make the truck THUMP at idle through the big 3.5" exhaust.

 

Impressive. Most impressive.

 

https://www.chevrolet.com/performance-parts/crate-engines/l8p

That’s a huge boost. Wonder what a proper h/c/I would net ya? 
 

 

Dunn Senior Enthusiast

Dunn

Posted
Posted

jeez, that seems massive to me.....know a little about engines but far from any pro

 

we would spend thousands just to get a few extra HP out of mx race bikes

carkhz316 Enthusiast

carkhz316

Posted
Posted

I remember being a kid 30 some years ago and having 300+ hp was supercar territory and mostly unheard of in anything without forced induction.

KARNUT Senior Enthusiast

KARNUT

Posted
Posted
1 hour ago, carkhz316 said:

I remember being a kid 30 some years ago and having 300+ hp was supercar territory and mostly unheard of in anything without forced induction.

I remember those days. Now everything I drive even the minivan is right around 300 HP. 

  • Like 1
Kjduvall Enthusiast

Kjduvall

Posted
Posted

ive been saying it for awhile, these 6.6 motors have soo much potential . they are neuterd from the factory. think about a 225/236 .620/.620 lift on a 113 +2 lsa or so cam , with some long tubes and that new 6.6 whipple blower............... it would be bonkers on some e85. im glad somebody is putting in some time (and money) to play with one. wish i had more cash to play with, id be rocking a 900+ hp 6.6.

Epsilon Plus Enthusiast

Epsilon Plus

Posted
  • Author
Posted (edited)

Instead of the blowers that just came out one could likely do this cam, springs, and 2" stainless works headers/true duals and a tune. The advantage of the blower would still be single kit, not opening the engine, and forced atmosphere at altitude. Its great to have tuning but the costs are bleh. I remember when ol HP Tuners was like $350 or something haha 

Edited by Epsilon Plus
  • 3 weeks later...
LTX402 Enthusiast

LTX402

Posted
Posted

I just bought an l8t for 4k when im done mechanically it will be an l8p. Going to be using the following in it:

l8p cam

Tsp .660 dual platinum valve springs with titanium retainers

Tsp Hardened pushrods

CHE trunion upgrade

Lt2 intake manifold

Lt5 tb

4” cai

1 7/8” Longtubes 

15% underdrive pulley

flex fuel sensor. 

Mind you the l8p put down 523 to the crank on 91 with the truck manifold and headers Im hoping for im hoping to make another 100hp to the crank with the extra mods and e85 ill post results when its finished 

  • Like 4
Epsilon Plus Enthusiast

Epsilon Plus

Posted
  • Author
Posted

I think the L8P is using LT1/2 cylinder heads. The combustion chamber and valve details lead me to believe that. I'm not aware of any port or valve dimension differences between them and the L8T though. The CC size is likely just to bump compression on the LTs.

NaturallyAspirated Enthusiast

NaturallyAspirated

Posted
Posted
On 3/29/2024 at 7:06 AM, Epsilon Plus said:

Just saw this today. Apparently at the end of last year GM Performance dropped an L8P crate engine. Looks to be just a cam (and likely valve springs) only L8T. Same intake/exhaust manifolds, compression...etc. It really showcases the monster potential of one of GMs greatest engines. Cam only and jumping from 87 to 91 it bumps from 401/464 to 523/543. That's a monster gain of 122hp and 79tq from a moderate cam size (relative to "big" aftermarket cams of 240+ duration and .600+ lift).

 

Cam is from an LT2 P/N: 12736191 other part number change on the crate engine is the cylinder heads but that's very likely only the stronger valve springs to support the increased ~.50 lift. Duration increases from 193/199 to 218/231. That exhaust duration should make the truck THUMP at idle through the big 3.5" exhaust.

 

Impressive. Most impressive.

 

https://www.chevrolet.com/performance-parts/crate-engines/l8p


if only I was a rich man… to have one of these L8P’s in our trucks…. wow.

LTX402 Enthusiast

LTX402

Posted
Posted
On 4/21/2024 at 10:13 AM, Epsilon Plus said:

I think the L8P is using LT1/2 cylinder heads. The combustion chamber and valve details lead me to believe that. I'm not aware of any port or valve dimension differences between them and the L8T though. The CC size is likely just to bump compression on the LTs.

Yea theyre the same as the lt1/2/l86  the only difference between those heads and the l8t heads are the springs. The l8t uses the same weaker springs as the l83 because they use the same cam. Im going to be using much nicer springs in my poormans l8p though .660 dual platinums along with some chromoly pushrods i plan to rev it higher than they reved the actual l8p being that mine will have the lt2 intake lt5 tb a monster intake pipe and longtubes. I expect it to make about 500 whp on e85. Should be nice and tame im coming off a 650whp turbo l83 build 

Kjduvall Enthusiast

Kjduvall

Posted
Posted

i bet TEA (total engine airflow) could cnc port those heads/mill em a bit and get a little more comp out of em, that would work good with the e85.

LTX402 Enthusiast

LTX402

Posted
Posted
On 4/30/2024 at 8:13 AM, Kjduvall said:

i bet TEA (total engine airflow) could cnc port those heads/mill em a bit and get a little more comp out of em, that would work good with the e85.

Yea there are actually a set of gm cnc heads from the hot cam package that id like to use maybe next year when i have a little more budget to work with. 

  • 2 weeks later...
SanchezC10 New Member

SanchezC10

Posted
Posted
On 4/20/2024 at 8:08 PM, LTX402 said:

I just bought an l8t for 4k when im done mechanically it will be an l8p. Going to be using the following in it:

l8p cam

Tsp .660 dual platinum valve springs with titanium retainers

Tsp Hardened pushrods

CHE trunion upgrade

Lt2 intake manifold

Lt5 tb

4” cai

1 7/8” Longtubes 

15% underdrive pulley

flex fuel sensor. 

Mind you the l8p put down 523 to the crank on 91 with the truck manifold and headers Im hoping for im hoping to make another 100hp to the crank with the extra mods and e85 ill post results when its finished 

Where will you be getting the L8p cam from? I don't see anyone selling it atm. I also have a L8T and was thinking of doing something similar for my 70 C10 project. I'm also looking at going for SDPC SDR230239LT that Gas Monkey Garage used for their L8T C10 if the L8P cam doesn't become available in the next month or so.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,947
    Total Members
    8,960
    Most Online
    Sothpaw27
    Newest Member
    Sothpaw27
    Joined

  • Who's Online   0 Members, 0 Anonymous, 442 Guests (See full list)

    • There are no registered users currently online

  • Latest Articles

  • Posts

    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      www.enginelabs.com/news/what-i-learned-today-bearing-clearances-vs-oil-viscosities/     www.enginelabs.com/news/oil-viscosity-can-the-numbers-be-misleading/ The Big Lie… Coming full circle to the reason Lake discusses the Porsche engines in particular. Based on the 2000 samples in the SPEEDiagnostix database, increasing the oil viscosity in these engines, even those run on the track, showed no significant difference in results.   The smoking gun was in the oil chemistry. That is where the data shows higher instances of more wear. Molybdenum was the key; the higher the amount, the less the wear. Speed postulates that higher viscosity oils have more thickeners to artificially inflate their viscosity numbers. These thickeners lose viscosity under shear, and the result is that not all oils of the same viscosity have the same shear stability.   Having enough viscosity is the most important characteristic, but according to Speed, once that required viscosity level is reached, additive chemistry matters more than additional viscosity. Speed also states, oil pressure problems on the racetrack aren’t a viscosity problem; it’s an oiling system problem. Running a thicker oil is just a band-aid for an underlying oiling system problem.
    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      Can it still be Assembled II?   Viscosity on the decline by various means. Heat on the rise making that worse. Engine RPM in the tank. Smaller motors with more boost trying to emulate an electric motor. Full torque, zero rpm. Then we will triple the OCI. Argh.    But wait....there is more. LSPI has pushed a shift from Ca to Mg and as that cost more PLUS the run to lower sulfur compounds the TBN is moving in the wrong direction for the increased OCI's demanded.    That not being enough to placate a demand for a parameter they can't measure the other sulfur bearing compounds are also under attack. That would be zinc and phosphorus sulfonate compounds. To some degree those are being replaced with boron esters and others, i.e. titanium ect. All of which have shorter service lives. And there there is the "Secrete Sauce" marketing for AW adds that 'Can't be detected by UOA's" but trust me because I (the blenders) never ever lie.    Spoiler alert; ALL additives are sacrificial! Smaller amounts of the old blended with less robust versions of the new do not equal longer service lives. So what are the blenders recommending? Wait for it.......   MOVING THE GOAL POSTS! OMG      Let's declare the long standing TAN/TBN crossover irrelevant and tell people that soot is a great 'graphite' based lubricant which can aid tribo films. Wait, what? Let's declare that the standards used for oxidation and nitration were to conservative and can be expanded. Let's tell them that because GDI fuel dilution, although being a VISCOSITY KILLER and an acid generator is actually okay because we have better base oils that limit viscosity failure limits. (Said knowing this is measured in fractions of a centipoise and in bases not commonly used in shelf oils)   Lying from the heart is not just the new normal but we have a public, a very young public, that is so ignorant of the facts and so sure of their "RESEARCH" into AI driven models base in regurgitated  instead of scientific research based unvarnished, peer reviewed FACTS that the incoming guard is loosing their grip on reality and the OEM's are tickled pink while the blends bend the knee.    You have an ever limited set of tools to work with. And sooner or later those will be taken from you as the API and the EPA strangle the last remaining fluids from the system. What you have left is your wits. If you care to use them.    At some point in the very near future it will not longer be possible to do "What is best for the machine", and be replaced with "The best you have access too". You WILL be rewarded with half the life and twice the cost. That isn't that hard to predict.         
    • Chuck FB
      Software Update

      By Chuck FB · Posted

      I trust you saw the other comment where he knew what he was talking about !. Yes, these darned newer vehicles with all their so smart they are stupid technology, goes and drains the battery down. As you might see my other comment, I installed a Noco 5 battery tender under the hood and at this point still have the cord routed so I have to lift the hood and then plug it in but am typically parked in a garage or a shed so its not risking the engine hood in the wind. That way I am assured or hopefully so of not finding I have a battery drawn down and can't even start the truck and that also damages the battery to draw it down too far. 
    • Chuck FB
      Software Update

      By Chuck FB · Posted

      I guess no surprise my guesses were wrong !, at least now I know if I ever happen to see it grayed out in my own truck as to what is going on.    I never happened to catch my truck with it grayed out, it seemed every time I would test to see if there was an update it never found anything and yet more than once I would check to see if there was an update and there was nothing, then a day later or even that same morning I would drive to town and after more than one engine shut down in town as I did my errands it would pop up that there is an update now ready to install and the only place I have a connection to the internet is at home by wifi so its not as if it grabbed the download while driving. I don't trust these new vehicles due to all the crap they can decide to do while sitting for some days not running and run the battery down so most of the time if I know the truck will sit for a few days I plug in the battery tender I have mounted under the hood and so the only time the truck must have downloaded software was when it was sitting in the garage where the signal is awful but I have that tender plugged in and somehow it managed to download it. I honestly detest all this crap, way to easy to leave a person stranded.    Since I don't trust any of it I don't do the install of the already downloaded software until I get home and sometimes have even sat in the truck to watch what its doing as its going through the process to its conclusion as its not like it is set up that it will tell you the next time you fire up the engine that the update that was initialed actually installed or installed properly. Yes I can go into the updates and see the list. After I go through the install where I feel its safe to do so in case it breaks down as a result, I will plug in the battery tender after the fact to recharge as I don't know how much power its taking just to do the install and that can take a while for it to install. 
    • nfisherman
      Software Update

      By nfisherman · Posted

      Thanks for the reply. All settings were correct and the engine was off, as it was supposed to be. It turned out to be something simple. I took a drive for about an hour. I must have had a low battery without knowing it. The voltage gauge on the display looked ok. At the end of my drive, I shut off the engine and the update prompt came up and it updated normally. It’s ironic because one of the features of the update is a reduction of battery drain. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...