GenV LT heads on Gen3 LS block
02-02-2023, 12:42 PM
#61
TECH Apprentice
Thread Starter
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.
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.
until nobody has # we all just assume...
Further i havent thought of this swap myself, i didnt just come up with it... people do it, and keep on doing it. so i assume there is a positive reason..
You and me have not done it, so we both dont know... i am a just bit more curious than others i think ...
02-02-2023, 01:43 PM
#62
TECH Senior Member
OK, let's assume we have 2 LS engines, one with GOOD Gen IV LS3 heads, and the other with Gen V LT heads. MAYBE the LT headed one puts out 10-15 more HP.
Is it worth jumping thru the hoops necessary to make the LT heads work, or are you better off bolting together a known combo for similar power numbers?
If there were huge gains to be had doing this, EVERYBODY would jump on this wagon and go for it. BUT, that's not happening, or these forums would be awash with build threads and dyno tests up our collective wazoo.
Is it worth jumping thru the hoops necessary to make the LT heads work, or are you better off bolting together a known combo for similar power numbers?
If there were huge gains to be had doing this, EVERYBODY would jump on this wagon and go for it. BUT, that's not happening, or these forums would be awash with build threads and dyno tests up our collective wazoo.
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Sebambam (02-02-2023)
02-02-2023, 02:20 PM
#63
Canted valves, higher compression, tall ports......yep sounds fun. It makes more sense on a stock build or conversion, you already need the upgraded parts.
02-02-2023, 03:20 PM
#64
TECH Apprentice
Thread Starter
OK, let's assume we have 2 LS engines, one with GOOD Gen IV LS3 heads, and the other with Gen V LT heads. MAYBE the LT headed one puts out 10-15 more HP.
Is it worth jumping thru the hoops necessary to make the LT heads work, or are you better off bolting together a known combo for similar power numbers?
If there were huge gains to be had doing this, EVERYBODY would jump on this wagon and go for it. BUT, that's not happening, or these forums would be awash with build threads and dyno tests up our collective wazoo.
Is it worth jumping thru the hoops necessary to make the LT heads work, or are you better off bolting together a known combo for similar power numbers?
If there were huge gains to be had doing this, EVERYBODY would jump on this wagon and go for it. BUT, that's not happening, or these forums would be awash with build threads and dyno tests up our collective wazoo.
in the mentioned combo...it makes no sense.
simply becuase : Great LS3 heads it cant get any better as a stock head.
most likly a 6.2 SBE? lets say yes.
CORRECT NO NEED TO DO THIS also for this engine you ll look at LT1 or LT4 heads, those cost a couple $$
this engine is a great combo and by no means (to me a Budget build) just becuase of the costs of getting this LS3
Or do you consider to put LS3 heads on a Truck 6L engine?
then its still not budget because the LS3 heads = $$$
and you have to get a rec port intake
Lets take my reality and how this whole thread started:
LM7 engine for 120$ from the local Fb marketplace.
Main / rod Bearings and Rings 100$
Stock Bore 5.3
LT /L83 heads 80$
I outlined above the differences in aftemarket parts needed, cam, valvesprings, blockoffs, intake.
Besides the Blockoffs all this mods will be needed on your LS3 as well ( If you use the intake that comes with you have to spend 300$ for injectors only )
Lets put a "build Budget of 1800$" on it lets say thats all i have ... for the Longblock
Is it worth it in this combo?
PS: and yes people do it i think, why else woul BTR build and promote parts for this swap? Maybe the cam is needed to take full advantage of the head gains?
I know I **** everybody off now , but let's be honest this thread is making everybody thinking one way or another.
And that's good .
sbc builds chaged over the time too and improved with part swaps if nobody would have tried vortec heads on a 350 we would still think camel humps are the peak of gm castings.
And Vortec heads came 30 years after the camel humps.
Last edited by Sebambam; 02-02-2023 at 03:45 PM.
02-02-2023, 03:21 PM
#65
TECH Apprentice
Thread Starter
with stock valve springs and a stock LM7 cam
then we could see the real gain , head to head
i will do cam and valve springs regardless
02-02-2023, 04:19 PM
#66
TECH Senior Member
YoU are right
in the mentioned combo...it makes no sense.
simply becuase : Great LS3 heads it cant get any better as a stock head.
most likly a 6.2 SBE? lets say yes.
CORRECT NO NEED TO DO THIS also for this engine you ll look at LT1 or LT4 heads, those cost a couple $$
this engine is a great combo and by no means (to me a Budget build) just becuase of the costs of getting this LS3
Or do you consider to put LS3 heads on a Truck 6L engine?
then its still not budget because the LS3 heads = $$$
and you have to get a rec port intake
Lets take my reality and how this whole thread started:
LM7 engine for 120$ from the local Fb marketplace.
Main / rod Bearings and Rings 100$
Stock Bore 5.3
LT /L83 heads 80$
I outlined above the differences in aftemarket parts needed, cam, valvesprings, blockoffs, intake.
Besides the Blockoffs all this mods will be needed on your LS3 as well ( If you use the intake that comes with you have to spend 300$ for injectors only )
Lets put a "build Budget of 1800$" on it lets say thats all i have ... for the Longblock
Is it worth it in this combo?
in the mentioned combo...it makes no sense.
simply becuase : Great LS3 heads it cant get any better as a stock head.
most likly a 6.2 SBE? lets say yes.
CORRECT NO NEED TO DO THIS also for this engine you ll look at LT1 or LT4 heads, those cost a couple $$
this engine is a great combo and by no means (to me a Budget build) just becuase of the costs of getting this LS3
Or do you consider to put LS3 heads on a Truck 6L engine?
then its still not budget because the LS3 heads = $$$
and you have to get a rec port intake
Lets take my reality and how this whole thread started:
LM7 engine for 120$ from the local Fb marketplace.
Main / rod Bearings and Rings 100$
Stock Bore 5.3
LT /L83 heads 80$
I outlined above the differences in aftemarket parts needed, cam, valvesprings, blockoffs, intake.
Besides the Blockoffs all this mods will be needed on your LS3 as well ( If you use the intake that comes with you have to spend 300$ for injectors only )
Lets put a "build Budget of 1800$" on it lets say thats all i have ... for the Longblock
Is it worth it in this combo?
Take an LQ4 or LQ9 Gen III 6.0. Still common and relatively inexpensive.
Add heads from a Gen IV truck rec port 6.0/6.2. Same basic thing, and cheaper than the LS3.
Rec port heads will not fit Gen III/IV 4.8/5.3.
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Sebambam (02-02-2023)
02-02-2023, 04:55 PM
#68
TECH Apprentice
Thread Starter
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Sebambam (02-02-2023)
02-03-2023, 02:10 AM
#71
LT heads do NOT impress me.....horribly inefficient
With that intake port size and location (the floor of the port raised 1.5" or so above the head deck) they should easily flow 50+ CFM more even as cast
They are close to 300 cc's stock and only flow around 305 CFM. The floor of the intake is at least 3/8 of an inch higher than even an LS7 head and its only flowing 305 CFM with a huge port!??
That's honestly kind of pathetic. Are they better ported.....sure but not by a huge margin.....340 - 350 CFM and now the port is even larger
A factory LS7 head is 270 cc's and flows 365 CFM right out of the box (with technically a lower intake port which is a disadvantage from a design perspective). My aftermarket 265 LS7 heads are 404 - 414 CFM depending on valve and porting options as another reference point.
In short the LS7 head crushes an LT1 Gen V head....its embarrassing its so bad. Hell my aftermarket 12 degree LS3 heads flows 385 - 390 CFM and that head is only 260 cc's.
The ONE thing they did to improve things in an LT Gen V deal is the move to direct injection.....that's worth gains in efficiency (fuel economy) and torque output but you wouldn't be running that in your LS deal either.
I could SHRINK the LT intake port with about 40 cc's of epoxy and pick it up 40 CFM in the process making it a bunch more efficient (and much higher airspeed). They really dropped the ball on the short turn of the intake laying it down and negating all of the gains that could have been had with such a tall ideal intake port location.
And the hooked exhaust port.....another mess to further reduce the effectiveness of the exhaust port and the cylinder heads potential output.
Honesty I have stayed away from messing with them for the most part because I was convinced that GM would have made a radical change in the port configuration/shape by now as the term low hanging fruit doesnt even begin to cut it. This port design is so easily improved on but it would require ADDING material in the right places to improve its flow characteristics (and subsequently a big gain in airspeed which is every bit as important as air volume).
So yeah.....no love for the LT Gen V heads here at Mamo Motorsports.....LOL
Naturally I have helped some folks with ported OEM LT castings and make them flow and perform better but I don't go out of my way looking for that business because at the end of the day its just not a product I can get real excited about
That doesnt mean that ported LT1 casting with 340 - 350 CFM's with direct injection cant make power.....
Its just that as a head designer by trade, I look at the location of the port, the size of the port, the size of the valve (and the valve angle) and I know I could have gotten sooo much more from that architecture....to me its a huge GM disappointment.
Consider these stock flow and port volume numbers and history of the LS / LT platform
1st Gen LS1 heads........................205 cc / 230 CFM
2nd Gen LS1 heads (243)..............211 cc / 255 CFM (nice gain with minimal volume increase is a winner)
Rect port LS3 heads..................... 260 cc / 315 CFM (Big gain in flow and a big gain in volume....so so in efficiency/airspeed)
Rect port LS7 heads..................... 270 cc / 365 CFM (the pinnacle of OEM cylinder head architecture IMO.....10 more cc's over an LS3 but 50 more CFM!!)
LT Gen V heads............................290 cc / 305 CFM
Mamo 265 LS7 heads...................265 cc / 414 CFM Shameless plug only to show what a well designed smaller port is capable of (BIG airflow and BIG airspeed....that's the hot ticket to insane performance and its not easy to achieve)
With so much going for it in terms of the architecture/port location, LT heads flow worse than a decade older LS3 design with a taller port and a larger runner and a flatter valve angle! Poor design....very inefficient
You want your LS engine to make a bunch of power and accelerate hard....steer clear of an LT head and put a properly sized efficient aftermarket LS casting on it.....I may know a guy that can help
Hope this post was helpful
Catch you guys later
-Tony
With that intake port size and location (the floor of the port raised 1.5" or so above the head deck) they should easily flow 50+ CFM more even as cast
They are close to 300 cc's stock and only flow around 305 CFM. The floor of the intake is at least 3/8 of an inch higher than even an LS7 head and its only flowing 305 CFM with a huge port!??
That's honestly kind of pathetic. Are they better ported.....sure but not by a huge margin.....340 - 350 CFM and now the port is even larger
A factory LS7 head is 270 cc's and flows 365 CFM right out of the box (with technically a lower intake port which is a disadvantage from a design perspective). My aftermarket 265 LS7 heads are 404 - 414 CFM depending on valve and porting options as another reference point.
In short the LS7 head crushes an LT1 Gen V head....its embarrassing its so bad. Hell my aftermarket 12 degree LS3 heads flows 385 - 390 CFM and that head is only 260 cc's.
The ONE thing they did to improve things in an LT Gen V deal is the move to direct injection.....that's worth gains in efficiency (fuel economy) and torque output but you wouldn't be running that in your LS deal either.
I could SHRINK the LT intake port with about 40 cc's of epoxy and pick it up 40 CFM in the process making it a bunch more efficient (and much higher airspeed). They really dropped the ball on the short turn of the intake laying it down and negating all of the gains that could have been had with such a tall ideal intake port location.
And the hooked exhaust port.....another mess to further reduce the effectiveness of the exhaust port and the cylinder heads potential output.
Honesty I have stayed away from messing with them for the most part because I was convinced that GM would have made a radical change in the port configuration/shape by now as the term low hanging fruit doesnt even begin to cut it. This port design is so easily improved on but it would require ADDING material in the right places to improve its flow characteristics (and subsequently a big gain in airspeed which is every bit as important as air volume).
So yeah.....no love for the LT Gen V heads here at Mamo Motorsports.....LOL
Naturally I have helped some folks with ported OEM LT castings and make them flow and perform better but I don't go out of my way looking for that business because at the end of the day its just not a product I can get real excited about
That doesnt mean that ported LT1 casting with 340 - 350 CFM's with direct injection cant make power.....
Its just that as a head designer by trade, I look at the location of the port, the size of the port, the size of the valve (and the valve angle) and I know I could have gotten sooo much more from that architecture....to me its a huge GM disappointment.
Consider these stock flow and port volume numbers and history of the LS / LT platform
1st Gen LS1 heads........................205 cc / 230 CFM
2nd Gen LS1 heads (243)..............211 cc / 255 CFM (nice gain with minimal volume increase is a winner)
Rect port LS3 heads..................... 260 cc / 315 CFM (Big gain in flow and a big gain in volume....so so in efficiency/airspeed)
Rect port LS7 heads..................... 270 cc / 365 CFM (the pinnacle of OEM cylinder head architecture IMO.....10 more cc's over an LS3 but 50 more CFM!!)
LT Gen V heads............................290 cc / 305 CFM
Mamo 265 LS7 heads...................265 cc / 414 CFM Shameless plug only to show what a well designed smaller port is capable of (BIG airflow and BIG airspeed....that's the hot ticket to insane performance and its not easy to achieve)
With so much going for it in terms of the architecture/port location, LT heads flow worse than a decade older LS3 design with a taller port and a larger runner and a flatter valve angle! Poor design....very inefficient
You want your LS engine to make a bunch of power and accelerate hard....steer clear of an LT head and put a properly sized efficient aftermarket LS casting on it.....I may know a guy that can help
Hope this post was helpful
Catch you guys later
-Tony
__________________
www.mamomotorsports.com
Tony@MamoMotorsports.com
Anything worth doing is worth doing well. Build it right the first time....its alot cheaper than building it twice!!
www.mamomotorsports.com
Tony@MamoMotorsports.com
Anything worth doing is worth doing well. Build it right the first time....its alot cheaper than building it twice!!
Last edited by Tony @ Mamo Motorsports; 02-03-2023 at 08:13 AM.
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02-03-2023, 07:50 AM
#72
TECH Apprentice
Thread Starter
LT heads do NOT impress me.....horribly inefficient
With that intake port size and location (the floor of the port raised 1.5" or so above the head deck) they should easily flow 50+ CFM more even as cast
They are close to 300 cc's stock and only flow around 305 CFM. The floor of the intake is at least 3/8 of an inch higher than even an LS7 head and its only flowing 305 CFM with a huge port!??
That's honestly kind of pathetic. Are they better ported.....sure but not by a huge margin.....340 - 350 CFM and now the port is even larger
A factory LS7 head is 270 cc's and flows 365 CFM right out of the box (with technically a lower intake port which is a disadvantage from a design perspective). My aftermarket 265 LS7 heads are 404 - 414 CFM depending on valve and porting options as another reference point.
In short the LS7 head crushes an LT1 Gen V head....its embarrassing its so bad. Hell my aftermarket 12 degree LS3 heads flows 385 - 390 CFM and that head is only 260 cc's.
The ONE thing they did to improve things in an LT Gen V deal is the move to direct injection.....that's worth gains in efficiency (fuel economy) and torque output but you wouldn't be running that in your LS deal either.
I could SHRINK the LT intake port with about 40 cc's of epoxy and pick it up 40 CFM in the process making it a bunch more efficient (and much higher airspeed). They really dropped the ball on the short turn of the intake laying it down and negating all of the gains that could have been had with such a tall ideal intake port location.
And the hooked exhaust port.....another mess to further reduce the effectiveness of the exhaust port and the cylinder heads potential output.
Honesty I have stayed away from messing with them for the most part because I was convinced that GM would have made a radical change in the port configuration/shape by now as the term low hanging fruit doesnt even begin to cut it. This port design is so easily improved on but it would require ADDING material in the right places to improve its flow characteristics (and subsequently a big gain in airspeed which is every bit as important as air volume).
So yeah.....no love for the LT Gen V heads here at Mamo Motorsports.....LOL
Naturally I have helped some folks with ported OEM LT castings and make them flow and perform better but I don't go out of my way looking for that business because at the end of the day its just not a product I can get real excited about
That doesnt mean that ported LT1 casting with 340 - 350 CFM's with direct injection cant make power.....
Its just that as a head designer by trade, I look at the location of the port, the size of the port, the size of the valve (and the valve angle) and I know I could have gotten sooo much more from that arcitecture....to me its a huge GM disappointment.
Consider these stock flow and port volume numbers and history of the LS / LT platform
1st Gen LS1 heads........................205 cc / 230 CFM
2nd Gen LS1 heads (243)..............211 cc / 255 CFM (nice gain with minimal volume increase is a winner)
Rect port LS3 heads..................... 260 cc / 315 CFM (Big gain in flow and a big gain in volume....so so in efficiency/airspeed)
Rect port LS7 heads..................... 270 cc / 365 CFM (the pinnacle of OEM cylinder head architecture IMO.....10 more cc's over an LS3 but 50 more CFM!!)
LT Gen V heads............................290 cc / 305 CFM
Mamo 265 LS7 heads....................265 cc / 414 CFM Shameless plug only to show what a well designed smaller port is capable of (BIG airflow and BIG airspeed....that's the hot ticket to insane performance and its not easy to achieve)
With so much going for it in terms of the architecture/port location, LT heads flow worse than a decade older LS3 design with a taller port and a larger runner and a flatter valve angle! Poor design....very inefficient
You want your LS engine to make a bunch of power and accelerate hard....steer clear of an LT head and put a properly sized efficient aftermarket LS casting on it.....I may know a guy that can help
Hope this post was helpful
Catch you guys later
-Tony
With that intake port size and location (the floor of the port raised 1.5" or so above the head deck) they should easily flow 50+ CFM more even as cast
They are close to 300 cc's stock and only flow around 305 CFM. The floor of the intake is at least 3/8 of an inch higher than even an LS7 head and its only flowing 305 CFM with a huge port!??
That's honestly kind of pathetic. Are they better ported.....sure but not by a huge margin.....340 - 350 CFM and now the port is even larger
A factory LS7 head is 270 cc's and flows 365 CFM right out of the box (with technically a lower intake port which is a disadvantage from a design perspective). My aftermarket 265 LS7 heads are 404 - 414 CFM depending on valve and porting options as another reference point.
In short the LS7 head crushes an LT1 Gen V head....its embarrassing its so bad. Hell my aftermarket 12 degree LS3 heads flows 385 - 390 CFM and that head is only 260 cc's.
The ONE thing they did to improve things in an LT Gen V deal is the move to direct injection.....that's worth gains in efficiency (fuel economy) and torque output but you wouldn't be running that in your LS deal either.
I could SHRINK the LT intake port with about 40 cc's of epoxy and pick it up 40 CFM in the process making it a bunch more efficient (and much higher airspeed). They really dropped the ball on the short turn of the intake laying it down and negating all of the gains that could have been had with such a tall ideal intake port location.
And the hooked exhaust port.....another mess to further reduce the effectiveness of the exhaust port and the cylinder heads potential output.
Honesty I have stayed away from messing with them for the most part because I was convinced that GM would have made a radical change in the port configuration/shape by now as the term low hanging fruit doesnt even begin to cut it. This port design is so easily improved on but it would require ADDING material in the right places to improve its flow characteristics (and subsequently a big gain in airspeed which is every bit as important as air volume).
So yeah.....no love for the LT Gen V heads here at Mamo Motorsports.....LOL
Naturally I have helped some folks with ported OEM LT castings and make them flow and perform better but I don't go out of my way looking for that business because at the end of the day its just not a product I can get real excited about
That doesnt mean that ported LT1 casting with 340 - 350 CFM's with direct injection cant make power.....
Its just that as a head designer by trade, I look at the location of the port, the size of the port, the size of the valve (and the valve angle) and I know I could have gotten sooo much more from that arcitecture....to me its a huge GM disappointment.
Consider these stock flow and port volume numbers and history of the LS / LT platform
1st Gen LS1 heads........................205 cc / 230 CFM
2nd Gen LS1 heads (243)..............211 cc / 255 CFM (nice gain with minimal volume increase is a winner)
Rect port LS3 heads..................... 260 cc / 315 CFM (Big gain in flow and a big gain in volume....so so in efficiency/airspeed)
Rect port LS7 heads..................... 270 cc / 365 CFM (the pinnacle of OEM cylinder head architecture IMO.....10 more cc's over an LS3 but 50 more CFM!!)
LT Gen V heads............................290 cc / 305 CFM
Mamo 265 LS7 heads....................265 cc / 414 CFM Shameless plug only to show what a well designed smaller port is capable of (BIG airflow and BIG airspeed....that's the hot ticket to insane performance and its not easy to achieve)
With so much going for it in terms of the architecture/port location, LT heads flow worse than a decade older LS3 design with a taller port and a larger runner and a flatter valve angle! Poor design....very inefficient
You want your LS engine to make a bunch of power and accelerate hard....steer clear of an LT head and put a properly sized efficient aftermarket LS casting on it.....I may know a guy that can help
Hope this post was helpful
Catch you guys later
-Tony
this one is basically closing this thread
thanks to everybody who kept up with my annoying ***
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G Atsma (02-03-2023)
02-03-2023, 10:45 AM
#73
TECH Senior Member
At least you have now heard it from the pro...
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G Atsma (02-03-2023)
02-03-2023, 02:29 PM
#75
LT heads do NOT impress me.....horribly inefficient
With that intake port size and location (the floor of the port raised 1.5" or so above the head deck) they should easily flow 50+ CFM more even as cast
They are close to 300 cc's stock and only flow around 305 CFM. The floor of the intake is at least 3/8 of an inch higher than even an LS7 head and its only flowing 305 CFM with a huge port!??
That's honestly kind of pathetic. Are they better ported.....sure but not by a huge margin.....340 - 350 CFM and now the port is even larger
A factory LS7 head is 270 cc's and flows 365 CFM right out of the box (with technically a lower intake port which is a disadvantage from a design perspective). My aftermarket 265 LS7 heads are 404 - 414 CFM depending on valve and porting options as another reference point.
In short the LS7 head crushes an LT1 Gen V head....its embarrassing its so bad. Hell my aftermarket 12 degree LS3 heads flows 385 - 390 CFM and that head is only 260 cc's.
The ONE thing they did to improve things in an LT Gen V deal is the move to direct injection.....that's worth gains in efficiency (fuel economy) and torque output but you wouldn't be running that in your LS deal either.
I could SHRINK the LT intake port with about 40 cc's of epoxy and pick it up 40 CFM in the process making it a bunch more efficient (and much higher airspeed). They really dropped the ball on the short turn of the intake laying it down and negating all of the gains that could have been had with such a tall ideal intake port location.
And the hooked exhaust port.....another mess to further reduce the effectiveness of the exhaust port and the cylinder heads potential output.
Honesty I have stayed away from messing with them for the most part because I was convinced that GM would have made a radical change in the port configuration/shape by now as the term low hanging fruit doesnt even begin to cut it. This port design is so easily improved on but it would require ADDING material in the right places to improve its flow characteristics (and subsequently a big gain in airspeed which is every bit as important as air volume).
So yeah.....no love for the LT Gen V heads here at Mamo Motorsports.....LOL
Naturally I have helped some folks with ported OEM LT castings and make them flow and perform better but I don't go out of my way looking for that business because at the end of the day its just not a product I can get real excited about
That doesnt mean that ported LT1 casting with 340 - 350 CFM's with direct injection cant make power.....
Its just that as a head designer by trade, I look at the location of the port, the size of the port, the size of the valve (and the valve angle) and I know I could have gotten sooo much more from that architecture....to me its a huge GM disappointment.
Consider these stock flow and port volume numbers and history of the LS / LT platform
1st Gen LS1 heads........................205 cc / 230 CFM
2nd Gen LS1 heads (243)..............211 cc / 255 CFM (nice gain with minimal volume increase is a winner)
Rect port LS3 heads..................... 260 cc / 315 CFM (Big gain in flow and a big gain in volume....so so in efficiency/airspeed)
Rect port LS7 heads..................... 270 cc / 365 CFM (the pinnacle of OEM cylinder head architecture IMO.....10 more cc's over an LS3 but 50 more CFM!!)
LT Gen V heads............................290 cc / 305 CFM
Mamo 265 LS7 heads...................265 cc / 414 CFM Shameless plug only to show what a well designed smaller port is capable of (BIG airflow and BIG airspeed....that's the hot ticket to insane performance and its not easy to achieve)
With so much going for it in terms of the architecture/port location, LT heads flow worse than a decade older LS3 design with a taller port and a larger runner and a flatter valve angle! Poor design....very inefficient
You want your LS engine to make a bunch of power and accelerate hard....steer clear of an LT head and put a properly sized efficient aftermarket LS casting on it.....I may know a guy that can help
Hope this post was helpful
Catch you guys later
-Tony
With that intake port size and location (the floor of the port raised 1.5" or so above the head deck) they should easily flow 50+ CFM more even as cast
They are close to 300 cc's stock and only flow around 305 CFM. The floor of the intake is at least 3/8 of an inch higher than even an LS7 head and its only flowing 305 CFM with a huge port!??
That's honestly kind of pathetic. Are they better ported.....sure but not by a huge margin.....340 - 350 CFM and now the port is even larger
A factory LS7 head is 270 cc's and flows 365 CFM right out of the box (with technically a lower intake port which is a disadvantage from a design perspective). My aftermarket 265 LS7 heads are 404 - 414 CFM depending on valve and porting options as another reference point.
In short the LS7 head crushes an LT1 Gen V head....its embarrassing its so bad. Hell my aftermarket 12 degree LS3 heads flows 385 - 390 CFM and that head is only 260 cc's.
The ONE thing they did to improve things in an LT Gen V deal is the move to direct injection.....that's worth gains in efficiency (fuel economy) and torque output but you wouldn't be running that in your LS deal either.
I could SHRINK the LT intake port with about 40 cc's of epoxy and pick it up 40 CFM in the process making it a bunch more efficient (and much higher airspeed). They really dropped the ball on the short turn of the intake laying it down and negating all of the gains that could have been had with such a tall ideal intake port location.
And the hooked exhaust port.....another mess to further reduce the effectiveness of the exhaust port and the cylinder heads potential output.
Honesty I have stayed away from messing with them for the most part because I was convinced that GM would have made a radical change in the port configuration/shape by now as the term low hanging fruit doesnt even begin to cut it. This port design is so easily improved on but it would require ADDING material in the right places to improve its flow characteristics (and subsequently a big gain in airspeed which is every bit as important as air volume).
So yeah.....no love for the LT Gen V heads here at Mamo Motorsports.....LOL
Naturally I have helped some folks with ported OEM LT castings and make them flow and perform better but I don't go out of my way looking for that business because at the end of the day its just not a product I can get real excited about
That doesnt mean that ported LT1 casting with 340 - 350 CFM's with direct injection cant make power.....
Its just that as a head designer by trade, I look at the location of the port, the size of the port, the size of the valve (and the valve angle) and I know I could have gotten sooo much more from that architecture....to me its a huge GM disappointment.
Consider these stock flow and port volume numbers and history of the LS / LT platform
1st Gen LS1 heads........................205 cc / 230 CFM
2nd Gen LS1 heads (243)..............211 cc / 255 CFM (nice gain with minimal volume increase is a winner)
Rect port LS3 heads..................... 260 cc / 315 CFM (Big gain in flow and a big gain in volume....so so in efficiency/airspeed)
Rect port LS7 heads..................... 270 cc / 365 CFM (the pinnacle of OEM cylinder head architecture IMO.....10 more cc's over an LS3 but 50 more CFM!!)
LT Gen V heads............................290 cc / 305 CFM
Mamo 265 LS7 heads...................265 cc / 414 CFM Shameless plug only to show what a well designed smaller port is capable of (BIG airflow and BIG airspeed....that's the hot ticket to insane performance and its not easy to achieve)
With so much going for it in terms of the architecture/port location, LT heads flow worse than a decade older LS3 design with a taller port and a larger runner and a flatter valve angle! Poor design....very inefficient
You want your LS engine to make a bunch of power and accelerate hard....steer clear of an LT head and put a properly sized efficient aftermarket LS casting on it.....I may know a guy that can help
Hope this post was helpful
Catch you guys later
-Tony
Why do I still wanna see dyno numbers? lol
02-03-2023, 02:32 PM
#76
TECH Senior Member
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G Atsma (02-03-2023)
02-03-2023, 03:48 PM
#78
TECH Senior Member
02-04-2023, 08:35 AM
#80
TECH Apprentice
Thread Starter
We are the guys who dont care but 90% of new car buyers do , its about electric car vs Combustion, the fight is on