dixiebandit69

Can someone please explain WHY they made the exhaust port like this, instead of just giving it a straight shot out of the head like a Gen 1,2,3 or 4 head?
They were literally designing it from scratch; they could have made it any way they wanted. It's like they forgot all about the exhaust exit location until the last minute.
This seems like the engineering equivalent of not doing your homework the night before, then trying to finish it on the bus ride to school the next morning.

Sebambam

Who is actually saying/proving that there is no performance increase of LT Gen 5 heads?

lets go L83 to 706/862 heads this are the equivalent TRUCK heads (stock for stock)
or LS3 heads to LT1 heads.
I am sure there is a significant better flow and performance in the STOCK FOR STOCK LT heads.

LT is the evolution of the LS and they all Liter for Liter put down More HP/TQ than there LS equivalent.

I know it has to do with other things as well.. the Gen 5 Intakes are much better,as well as higher compression
However the Heads are always a essential part of power gains.

lets look at 5.3 s:
L83 ranges from 355-380 hp
LM7 from 270 -295 hp
this are the "simple' truck engines in comparison, do you really believe its just compression and intake?
thats basically up to 100hp gain on a stock engine

@RichardHoldener lets go lol

Che70velle

iTrader: (6)

Mast Motorsports
Darin Morgan
To name only a couple big names. Virtually every big shop hurried to get their hands on a set, to see what could be made of them. Other smaller shops have flowed them and discovered the issue as well. Intakes are killer! It’s a raised runner design that flows incredible. The exhaust side…ruined it. The gains made on the intake side, are a wash by the time you get the exhaust out of the engine. Forced induction isn’t such a big deal, as the N/A variants. Lots of folks had their hopes up when the Gen5 was released. As a package from GM, with its high compression ratio, piston crown design, direct injection, and bumped ignition timing, the engines run strong and the tables are met that GM set out to cross. Fuel mileage was number one on their list. The government’s fuel mileage standards had been bumped significantly and the only way you can go farther on a gallon of pump gas is to squeeze (compression) it harder. It also in turn makes more power. The fuel isn’t injected into the chamber until the end of the compression stroke, so detonation is practically irrelevant here. All-in-all it’s a great package. But head for head, the Gen4 LS outperforms them, from a pure performance standpoint.

G Atsma

As suspected, and there ya have it!

Sebambam

Link to the article?
I am sorry but a statement is not
A proof.
even though i like it.

For years we said truck heads are garbage and 243, 799s are the best cathedral heads until Rich Holdener put # to it

flow# heads for head.

I know I ask for alot I couldn't find flow # of stock L83 heads online at any source.

MuhThugga

I haven't paid any attention to the Gen V stuff because I don't own anything with a Gen V engine, but I did see that Edelbrock offers cylinder heads that move the exhaust port 1.5" to give it a straighter path: https://www.lsxmag.com/tech-stories/...ctor-jr-heads/

I'm not suggesting to buy the Edelbrock heads because that would make zero sense, but at least the article goes into the exhaust port location change and why Edelbrock felt it was necessary.

I guess my question would be this: After spending the money on the conversion to the Gen V heads, would it have cost the same amount to go with decent LS parts and which set up would perform better?

Sebambam

Thats a good question i just made the calc
and i kinda compared a close as possible, means cam specs LS/LT almost the same, Valve springs, as well as Intake incl. Injectors.

WE ASSUME THE HEADS ARE STOCK with JUST a SPRING UPGRADE
so a LS TRUCK head vs LT TRUCK head
so the LS is 250-300$ cheaper in the needed performance parts!
NO USED PARTS all NEW!!!
(PS: the LT has 2 intakes as a choice a truck l86 and a LT2 intake i took the LT2 in the calculation)


Both use LS9 Headgaskets!!

Now lets consider the LT heads flow Stock for Stock better, i doubt you can make the LS heads much better with 300$ (you saved over the LT stuff)?
if we mod the heads its in general a different story
a worked LT head flows awesome as well

PS i took the cam selection based on the Only cam available LT head swap cam from BTR ,i simply took the # and found a comparing LS cam
YES you can certainly get a cheaper cam arround 299 with less Lift ( .630-.6450 range)
For the LS intake i choose a TBSS intake for its flow # and it comes with 50lbs injectors.
However here i am sure the LT2 Intake flows better!

MuhThugga

I think you would need to include the cost of the heads in that comparison. You can do both LT and LS head prices, if the assumption is that you are starting with only an LS shortblock. Otherwise, it would be the cost added to the Gen V side as it is assumed that the LS guy is already starting with a set of cylinder heads and intake manifold (style depending on the engine at hand). There is also the cost of whatever block-off kit is needed for the direct injection ports.

Again, I'm not trying to crap on anything. I'm just trying to keep things as comparable as possible. In all honesty, I would be interested in seeing how the L83 heads and LT2 intake would perform on a flattop 5.3 in an NA setup.

Sebambam

Ok
I got a lm7 with 706 heads
150$ I took this 24x crank for another project and used the block as a mock up motor for a project.

Then I decided to build it.
I bought a 58x crank that was fresh machined 10/10 = 90$

I grabbed a Gen 4 timing cover and valve covers to complete the 58x conversion
And I swooped the set of good heads incl covers DI injectors, coils and exhaust manifolds all for 140$
Now you can make your Calc on what you think the heads are$$$ I say 80$

The blockoffs are 49$
https://www.summitracing.com/parts/i...xoCcqAQAvD_BwE

If you have a truck 6.0 that comes with 317 heads and you want to bump up compression you pay 150$ for 706 heads
300-400 for 243.

Remember this LT truck heads are not popular (yet) so easy to get for low $.

So I think this is a very minor cost.

I spoke to BTR on there cam , yes I can use it with a Gen 3 Ls they said if you have flat tops check for valve clearance..

My block has dished 5.3 pistons. I refreshed it anyways with new bearing and a dingleball hone + new rings for a NA build.

LS1Formulation

iTrader: (13)

Here's a thought... If you can get a port fuel injected intake for the Gen V engines, along with the pre-requisite block off plates, is there any reason you couldn't just run the Gen V complete longblock? Seems to me adapting that would be cheaper. Controlling the DI is the most expensive part of a Gen V conversion anyway.

Sebambam

I am not that familiar with Gen V but i think Gen V turbo guys like to use port injection for there setups.
theoretically yes you can run a Gen V longblock, block it off and go... however the ECU part is much easier on the LS i think with a standalone harness , there is not as much support yet for LTs i think. ( its more computers).

Sebambam

PS: i asked over there in the GEN V forum about flow # of LT heads
so we can compare to LS Flow #
Stock for Stock
https://ls1tech.com/forums/generatio...head-flow.html

here are LS flow #
https://www.lsenginediy.com/ultimate...r-heads-guide/

01CamaroSSTx

iTrader: (3)

The LS Frankenstein is right here..

https://www.motortrend.com/how-to/he...eal-kicks-***/

Sebambam

you know that completely fails the topic...
That's a aftermarket head $$$$$

grinder11

iTrader: (1)

I can't speak for the rest of the members here, but "statements" from Horace Mast and Darin Morgan are about as respectable as they come. A statement from Tony Mamo would really be valuable here, but IDK if he's done much with GenV stuff. If he hasn't, there must be a good reason.......

Sebambam

i respect them as well, however everybody that runs a business with speed parts has also business reasons to not envy stock part replacements and rather push there approach , But that is not the topic it was never said or asked if a LT head outflows a ported /worked or aftermarket head in any way . I am not chasing high hp #
It was simply about " hey i get a 100$ of LT heads will they increase power on a LS block?"
so therefore the Factory flow # of LS head compared to LT head are the focus.

if a 100$ set of L83 heads give you 50hp over a LS gen3/4 head would you consider doing that,
compared to send out LS heads for porting and spending 800-1500$ for cnc work?

Springs, cam, intake have to be adressed in both setups anyways (LS or LT)

Hotrodding is making it work with what you have !!

LS1Formulation

iTrader: (13)

Seriously, Richard Holdener needs to build a 5.3, dyno it, do what it takes to swap these heads on and dyno the same engine with them. This seems like it would be right in his wheelhouse.

Sebambam

jup, my words

G Atsma

Richard is usually on top of something that looks promising. He is all over the "next new thing".
If this were that, it would be a done deal.
It isn't, and he's not.
It appears that after all is said and done, cost and whatever else considered, the gains are what you get with a decent set of Gen III/IV heads.

LS1Formulation

iTrader: (13)

True, but he's been known to test theories that are known dead ends, just to settle online debates.