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

[Epsilon Plus]

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

[bruceb58]

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

[Pryme]

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]

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]

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]

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. 

[Kjduvall]

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]

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 April 1, 2024 by Epsilon Plus

[LTX402]

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 

[Epsilon Plus]

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]

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]

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]

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]

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. 

[SanchezC10]

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.