GenV LT heads on Gen3 LS block
#1
TECH Apprentice
Thread Starter
GenV LT heads on Gen3 LS block
hi
is it worth it for Sbe NA engine?
to use gen 5 heads?
What are the gaskets to use? Pushrods? I sa ict has a direct innj. Blockoff. And ls intake adapters.
do LS headers fit?
Thanks for the infos.
is it worth it for Sbe NA engine?
to use gen 5 heads?
What are the gaskets to use? Pushrods? I sa ict has a direct innj. Blockoff. And ls intake adapters.
do LS headers fit?
Thanks for the infos.
Popular Reply
02-03-2023, 02:10 AM
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!!
#2
LS headers do not fit. Pushrods, you will have to measure. Is your block a 5.7? I think that you have to have a 4" bore because of the valve size. The head takes a different alignment pin. No provision for steam crossover if you need that. Not sure if the threaded holes for the accessory drives are the same.Nice heads tho. I bet that you would be dollars ahead with nice LS3 heads. If you just want to do it---DO IT !!
The following users liked this post:
Sebambam (01-20-2023)
#3
TECH Apprentice
Thread Starter
LS headers do not fit. Pushrods, you will have to measure. Is your block a 5.7? I think that you have to have a 4" bore because of the valve size. The head takes a different alignment pin. No provision for steam crossover if you need that. Not sure if the threaded holes for the accessory drives are the same.Nice heads tho. I bet that you would be dollars ahead with nice LS3 heads. If you just want to do it---DO IT !!
It has to make $$ sense
Can you mount them with NO allignment pins? What headbolts do you use gen3 or gen 5?
#4
TECH Enthusiast
The following 2 users liked this post by dixiebandit69:
blackdak318 (02-01-2023), Jimbo1367 (05-16-2023)
#5
TECH Apprentice
Thread Starter
Btr and others offer a LT head swap cam kit and the NA performance # look really good.
I can get a cheap , complete set of l83 heads for my LM7 budget build.
the heads supposedly flow really good # and bolt on.
It could be a good budget performance upgrade
I can get a cheap , complete set of l83 heads for my LM7 budget build.
the heads supposedly flow really good # and bolt on.
It could be a good budget performance upgrade
#6
TECH Enthusiast
Can you show any examples of someone doing this swap?
The following 4 users liked this post by dixiebandit69:
#7
12 Second Club
iTrader: (13)
There is no "budget" build when trying to use Gen V heads on a Gen III or IV. Tick sells a tool to enlarge the dowel holes, it's $190. I think it needs to be used with their fixture, which is $450. You can't just set the heads on the block without alignment dowels. By the time you're done with this swap, you could have had a set of Trick Flow heads that would seriously outflow a pair of L83 heads.
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#8
TECH Apprentice
Thread Starter
Guys
here is the Cam:
https://briantooleyracing.com/btr-lt...s-engines.html
here is a simple DIY how to open up the dowel positions for LS blocks with a step drill
+ adding 2x 10 mm bolts
Other than that its bolt on, it seems
Seems like 2 of the accessories holes are in the same place which can hold the truck accessory easy.
the Coil harness can be swapped to the LS coil harness for "plug n play"
here is the Cam:
https://briantooleyracing.com/btr-lt...s-engines.html
here is a simple DIY how to open up the dowel positions for LS blocks with a step drill
+ adding 2x 10 mm bolts
Other than that its bolt on, it seems
Seems like 2 of the accessories holes are in the same place which can hold the truck accessory easy.
the Coil harness can be swapped to the LS coil harness for "plug n play"
Last edited by Sebambam; 01-21-2023 at 08:17 AM.
The following users liked this post:
G Atsma (01-24-2023)
#12
ModSquad
iTrader: (6)
Going to be a cobbled up letdown. The Gen5 heads simply don’t perform, which is why you don’t see the gen5 stuff take off. I’ve seen quite a few guys do a gen5 swap, only to take it out and go back to LS. You’ll end up doing this twice, which always costs more in the long run. GM announced recently their commitment to a new Gen6 engine. Hopefully they revise the Gen5 issues on this next platform.
The following 3 users liked this post by Che70velle:
#13
TECH Apprentice
Thread Starter
Going to be a cobbled up letdown. The Gen5 heads simply don’t perform, which is why you don’t see the gen5 stuff take off. I’ve seen quite a few guys do a gen5 swap, only to take it out and go back to LS. You’ll end up doing this twice, which always costs more in the long run. GM announced recently their commitment to a new Gen6 engine. Hopefully they revise the Gen5 issues on this next platform.
#14
TECH Senior Member
The following users liked this post:
Sebambam (01-24-2023)
#16
12 Second Club
iTrader: (13)
Scarce? You need to take a trip from TC down by me. There are no less than 3 huge pull your own yards that have HUNDREDS of LS engines in trucks, vans, and SUVs at all times. I have never went in there and not seen at least a few 6.0s, aluminum 5.3s, and other gems ( an L92 once ). But in terms of 5.3s/4.8s, there are too many to count. Not to mention, every place sells complete engines ( accessories and all ) for under $300.
#17
TECH Apprentice
Thread Starter
so why would companies like BTR & ICT offer of the shelve parts for it? Just asking for a friend...lol
I'm not trying to be a Di**, but it seems to become a interesting option since the LT heads flow really well.
i remember a few years ago everybody was like " dump the truck heads,, take LS1,2 heads", or "317 heads are best for boost" well since RICHARD HOLDENER proved different the approaches changed.
I'm not trying to be a Di**, but it seems to become a interesting option since the LT heads flow really well.
i remember a few years ago everybody was like " dump the truck heads,, take LS1,2 heads", or "317 heads are best for boost" well since RICHARD HOLDENER proved different the approaches changed.
#18
TECH Apprentice
Thread Starter
#19
TECH Apprentice
Thread Starter
Here it comes...
now I'll shock you completely.
The BLOCK I'm using is a 24x. The crank is a fresh 58x .
I have a gen4 timing cover to accommodate the front cam sensor location.
+ the L83 complete heads.
NOW that's A FRANKENSTEIN....
#USEWHATYOUHAVE
now I'll shock you completely.
The BLOCK I'm using is a 24x. The crank is a fresh 58x .
I have a gen4 timing cover to accommodate the front cam sensor location.
+ the L83 complete heads.
NOW that's A FRANKENSTEIN....
#USEWHATYOUHAVE
The following users liked this post:
headsup9550 (07-06-2023)
#20
L83 heads for smaller ls1 bore, basically sane as ls3 heads. I'm going to drum up a bastard child ls1 lt head setup. The lt heads are great heads especially for na builds
The following 2 users liked this post by k8busa:
headsup9550 (07-06-2023), Sebambam (01-25-2023)