Square Port heads vs. Cathedral Port heads
10-26-2010 | 06:24 PM
#141
So Brian, You say it realy is the oem style intake that is holding the square port heads back.
Ultimately, I dont beleive that aftermarket heads should really be compared to the factory square port heads. The oem heads should be compared to each other, and I beleive the square ports have more potential - oem to oem.
Lets compare aftermaket square ports to the aftermarket cathedral's
Ultimately, I dont beleive that aftermarket heads should really be compared to the factory square port heads. The oem heads should be compared to each other, and I beleive the square ports have more potential - oem to oem.
Lets compare aftermaket square ports to the aftermarket cathedral's
https://ls1tech.com/forums/generatio...-square-3.html
10-26-2010 | 06:25 PM
#142
Id be curious to see as to what would happen if you took some of these higher horsepower fast intake engines and put a carb style intake on them?will pwer go up/down
will torque curve shift but peak the same?
would a l92 based head ahve a decisive advantage over a cath port head if they were both carbed?
Brian,kaltech,melsie68,any one else care to share there opinion?
will torque curve shift but peak the same?
would a l92 based head ahve a decisive advantage over a cath port head if they were both carbed?
Brian,kaltech,melsie68,any one else care to share there opinion?
It was a very stout combo with our new 245 cathedral heads making around 700 HP....I believe it made 711 with the FAST intake (unported by the way in a fairly aggressive 468 CID build) and 28 more HP (peak to peak) with the MAST Motorsports two piece single plane race intake (a very impressive tall "spider style" manifold).
However, the much longer runner FAST had a 40 ft/lb advantage at 4000 RPM's (that's quite substantial) and made 20 more ft/lbs of peak torque but obviously the torque curve rolled over sooner.
IMO thats to be expected due once again to not only the length of the runners but the fact the FAST runner length is the exact same in every cylinder versus a much shorter spider style intake with shorter runners on the inside and longer runners on the outside.
Honestly, I'm building a 454 in a couple of months with the same AFR 245 heads....I would give up the extra torque in a minute (its not going to hook either way) to get the extra 28 ponies peak and better RPM potential the single plane offered but I'm not willing to compromise the stealthy look of my Vette with a sizable hood scope to properly package the single plane / top mounted TB.
As a pure test of manifold design and how it effects the power curve this type of back to back testing is priceless.
The other glaring fact is that on most applications that are more street/strip oriented....especially those with hydraulic valvetrains, the long runner FAST is a very effective piece augmenting the bulk of the curve that application was designed to positively impact.
Cheers,
Tony
10-26-2010 | 06:30 PM
#143
So Brian, You say it realy is the oem style intake that is holding the square port heads back.
Ultimately, I dont beleive that aftermarket heads should really be compared to the factory square port heads. The oem heads should be compared to each other, and I beleive the square ports have more potential - oem to oem.
Lets compare aftermaket square ports to the aftermarket cathedral's
Ultimately, I dont beleive that aftermarket heads should really be compared to the factory square port heads. The oem heads should be compared to each other, and I beleive the square ports have more potential - oem to oem.
Lets compare aftermaket square ports to the aftermarket cathedral's
The reason I was asking is because Greg used to argue this same topic with me, but after the results continued to come in, he agreed. Coleman Roddy running 9.15 on motor with a Fast and a hyd roller cam and James Day (TXCAMSS) running 9.30's with a Fast and hyd roller.
The square port heads with Fast intakes and hyd roller cams just don't seem to be as fast. This is not because the ports are square, it's because the ports and valves tend to be too big to work well with a long runner Fast intake.
The square port heads with Fast intakes and hyd roller cams just don't seem to be as fast. This is not because the ports are square, it's because the ports and valves tend to be too big to work well with a long runner Fast intake.
10-26-2010 | 07:25 PM
#144
So Brian, You say it realy is the oem style intake that is holding the square port heads back.
Ultimately, I dont beleive that aftermarket heads should really be compared to the factory square port heads. The oem heads should be compared to each other, and I beleive the square ports have more potential - oem to oem.
Lets compare aftermaket square ports to the aftermarket cathedral's
Ultimately, I dont beleive that aftermarket heads should really be compared to the factory square port heads. The oem heads should be compared to each other, and I beleive the square ports have more potential - oem to oem.
Lets compare aftermaket square ports to the aftermarket cathedral's
It does in fact take a really well designed cathedral port head with a smaller cross section (and a non raised runner) to compete with the latest offering from the general which in fact has the benefits I previously mentioned to help out the airflow curve in a substantial way.
However, if are wanting to compare a smaller high efficient port design to a larger less efficient design (in spite of how the peak intake numbers compare, although at this point they would be close) it's the delivery of the power curve thats more greatly effected....and especially if we are discussing lower RPM part throttle operation....this is NEVER reflected in the dyno curve at low RPM because that is WOT comparisons....its a feel thing you have to experience to understand and its for real. So when everyone points to the rect port heads dyno curve to compare low RPM data to a cathedral its a waste of time....yes its valid info but who in their right mind actually floors the accelerator pedal at 2800 or even 3400 RPM's....you most certainly downshift to a lower gear at that point.
Old school guys who have previously owned a BBC oval port performance motor versus a rectangular port engine and had the opportunity to experience both in the same vehicle will know exactly what I'm talking about....even if the peak power numbers were close, and the track performance was close, the drivability and low RPM torque at part throttle is night and day better with the smaller high velocity oval port heads. Hell the same car felt faster driving around town even if it wasn't....
The new LS3/L92 heads are a leap forward in a big way from the older OEM cathedral heads....no doubt about it, but IMO looking at them purely from a design stand point they are not terribly efficient and leave quite a bit of room for improvement....but thats all the good news honestly. As the aftermarket continues to invest time in building clean sheet design square port heads, the performance potential of these engines will go even higher.
Im confident I could take an L92 head and make it 20 cc's smaller and improve its flow at the same time....if that was the case what do you think the outcome would be come dyno and track day? The head would be alot more efficient and the power curve would certainly reflect that. Wanna make an L92/LS3 head better....spark up the welder and/or grab a can of your favorite epoxy....make it more efficient as well as adding CFM....don't just make a big head larger in search of added CFM, but unfortunately that's not very practical and to really accomplish this you need a clean sheet design casting to work with. Its the same argument we made 7 years ago when we launched the AFR 205.....everyone scoffed at it originally....a smaller port....what were they thinking?? But a port that head 5 cc's less finished volume than a stock LS6 head (the best OEM port at the time) and flowed almost 50 more CFM's. Alot more power in a package that felt like it wanted to explode down low if you were smart enough not to over cam the car.
I'm not sure why there is so much controversy lately with cathedral and rect port LS offerings....they both have their place in the world....they both have their upsides....and they both have their downsides. Picking the right head is just as important, if not more important than picking the right cam....it just depends on what your setting out to accomplish.
Sorry for the semi-lengthy rant but it seems no matter where I turn on the Internet the same BS keeps popping up everywhere with alot of the same players stirring the pot....hell it must be the topic of twenty threads in five different sections of just this particular site right now.
Hope this helped a few of you....
Thanks,
Tony
Last edited by Tony Mamo @ AFR; 10-26-2010 at 07:31 PM.
10-26-2010 | 07:54 PM
#146
TECH Enthusiast
Joined: Jan 2010
Posts: 578
Likes: 4
From: REALITY
Thats a good point and I agree with you, especially comparing OEM cathedral heads to OEM square port heads.....that's not even a contest. Much larger valve, much larger runner and CSA with a raised intake port that gives the port a much better vantage point (angle of attack) into the back of the intake valve and ultimately the combustion chamber.
It does in fact take a really well designed cathedral port head with a smaller cross section (and a non raised runner) to compete with the latest offering from the general which in fact has the benefits I previously mentioned to help out the airflow curve in a substantial way.
However, if are wanting to compare a smaller high efficient port design to a larger less efficient design (in spite of how the peak intake numbers compare, although at this point they would be close) it's the delivery of the power curve thats more greatly effected....and especially if we are discussing lower RPM part throttle operation....this is NEVER reflected in the dyno curve at low RPM because that is WOT comparisons....its a feel thing you have to experience to understand and its for real. So when everyone points to the rect port heads dyno curve to compare low RPM data to a cathedral its a waste of time....yes its valid info but who in their right mind actually floors the accelerator pedal at 2800 or even 3400 RPM's....you most certainly downshift to a lower gear at that point.
Old school guys who have previously owned a BBC oval port performance motor versus a rectangular port engine and had the opportunity to experience both in the same vehicle will know exactly what I'm talking about....even if the peak power numbers were close, and the track performance was close, the drivability and low RPM torque at part throttle is night and day better with the smaller high velocity oval port heads. Hell the same car felt faster driving around town even if it wasn't....
The new LS3/L92 heads are a leap forward in a big way from the older OEM cathedral heads....no doubt about it, but IMO looking at them purely from a design stand point they are not terribly efficient and leave quite a bit of room for improvement....but thats all the good news honestly. As the aftermarket continues to invest time in building clean sheet design square port heads, the performance potential of these engines will go even higher.
Im confident I could take an L92 head and make it 20 cc's smaller and improve its flow at the same time....if that was the case what do you think the outcome would be come dyno and track day? The head would be alot more efficient and the power curve would certainly reflect that. Wanna make an L92/LS3 head better....spark up the welder and/or grab a can of your favorite epoxy....make it more efficient as well as adding CFM....don't just make a big head larger in search of added CFM, but unfortunately that's not very practical and to really accomplish this you need a clean sheet design casting to work with. Its the same argument we made 7 years ago when we launched the AFR 205.....everyone scoffed at it originally....a smaller port....what were they thinking?? But a port that head 5 cc's less finished volume than a stock LS6 head (the best OEM port at the time) and flowed almost 50 more CFM's. Alot more power in a package that felt like it wanted to explode down low if you were smart enough not to over cam the car.
I'm not sure why there is so much controversy lately with cathedral and rect port LS offerings....they both have their place in the world....they both have their upsides....and they both have their downsides. Picking the right head is just as important, if not more important than picking the right cam....it just depends on what your setting out to accomplish.
Sorry for the semi-lengthy rant but it seems no matter where I turn on the Internet the same BS keeps popping up everywhere with alot of the same players stirring the pot....hell it must be the topic of twenty threads in five different sections of just this particular site right now.
Hope this helped a few of you....
Thanks,
Tony
It does in fact take a really well designed cathedral port head with a smaller cross section (and a non raised runner) to compete with the latest offering from the general which in fact has the benefits I previously mentioned to help out the airflow curve in a substantial way.
However, if are wanting to compare a smaller high efficient port design to a larger less efficient design (in spite of how the peak intake numbers compare, although at this point they would be close) it's the delivery of the power curve thats more greatly effected....and especially if we are discussing lower RPM part throttle operation....this is NEVER reflected in the dyno curve at low RPM because that is WOT comparisons....its a feel thing you have to experience to understand and its for real. So when everyone points to the rect port heads dyno curve to compare low RPM data to a cathedral its a waste of time....yes its valid info but who in their right mind actually floors the accelerator pedal at 2800 or even 3400 RPM's....you most certainly downshift to a lower gear at that point.
Old school guys who have previously owned a BBC oval port performance motor versus a rectangular port engine and had the opportunity to experience both in the same vehicle will know exactly what I'm talking about....even if the peak power numbers were close, and the track performance was close, the drivability and low RPM torque at part throttle is night and day better with the smaller high velocity oval port heads. Hell the same car felt faster driving around town even if it wasn't....
The new LS3/L92 heads are a leap forward in a big way from the older OEM cathedral heads....no doubt about it, but IMO looking at them purely from a design stand point they are not terribly efficient and leave quite a bit of room for improvement....but thats all the good news honestly. As the aftermarket continues to invest time in building clean sheet design square port heads, the performance potential of these engines will go even higher.
Im confident I could take an L92 head and make it 20 cc's smaller and improve its flow at the same time....if that was the case what do you think the outcome would be come dyno and track day? The head would be alot more efficient and the power curve would certainly reflect that. Wanna make an L92/LS3 head better....spark up the welder and/or grab a can of your favorite epoxy....make it more efficient as well as adding CFM....don't just make a big head larger in search of added CFM, but unfortunately that's not very practical and to really accomplish this you need a clean sheet design casting to work with. Its the same argument we made 7 years ago when we launched the AFR 205.....everyone scoffed at it originally....a smaller port....what were they thinking?? But a port that head 5 cc's less finished volume than a stock LS6 head (the best OEM port at the time) and flowed almost 50 more CFM's. Alot more power in a package that felt like it wanted to explode down low if you were smart enough not to over cam the car.
I'm not sure why there is so much controversy lately with cathedral and rect port LS offerings....they both have their place in the world....they both have their upsides....and they both have their downsides. Picking the right head is just as important, if not more important than picking the right cam....it just depends on what your setting out to accomplish.
Sorry for the semi-lengthy rant but it seems no matter where I turn on the Internet the same BS keeps popping up everywhere with alot of the same players stirring the pot....hell it must be the topic of twenty threads in five different sections of just this particular site right now.
Hope this helped a few of you....
Thanks,
Tony
.just kidding......So we can agree that oem is in one class and aftermarket is in its own class...?Whether or not people agree with the knowledge that has been thrown around all over the internet... If no one believes/sides with one over the other, we can say that more information has been posted than before.....
And somebody has learned something or walked away with a new perspective of how to look at heads,camshaft timing, exhaust systems, basically the entire combination.... Buying a product because they have a grasp or understanding of why they are buying the product vs, because I told it it would work....Whether cathedral or square port, its has to be put together properly.. I think we all agree or have a universal belief of this principle....
Bozz
10-26-2010 | 08:33 PM
#147
Sorry for the semi-lengthy rant but it seems no matter where I turn on the Internet the same BS keeps popping up everywhere with alot of the same players stirring the pot....hell it must be the topic of twenty threads in five different sections of just this particular site right now.
10-31-2010 | 11:31 AM
#149
Teching In
Joined: Apr 2008
Posts: 14
Likes: 0
I think this discussion has lost its value, I think the question should be how do we take this cheap but awesome flowing head and build more power then a pricey set of aftermarket heads? That's the hot rodders question. I know AFR and others have great heads but GM really threw everyone a curve with the ls3/l92 heads cost.
10-31-2010 | 12:54 PM
#151
Teching In
Joined: Sep 2010
Posts: 46
Likes: 0
From: Ft.Lauderdale, FL
I think this discussion has lost its value, I think the question should be how do we take this cheap but awesome flowing head and build more power then a pricey set of aftermarket heads? That's the hot rodders question. I know AFR and others have great heads but GM really threw everyone a curve with the ls3/l92 heads cost.
10-31-2010 | 01:51 PM
#152
Thats a good point and I agree with you, especially comparing OEM cathedral heads to OEM square port heads.....that's not even a contest. Much larger valve, much larger runner and CSA with a raised intake port that gives the port a much better vantage point (angle of attack) into the back of the intake valve and ultimately the combustion chamber.
It does in fact take a really well designed cathedral port head with a smaller cross section (and a non raised runner) to compete with the latest offering from the general which in fact has the benefits I previously mentioned to help out the airflow curve in a substantial way.
However, if are wanting to compare a smaller high efficient port design to a larger less efficient design (in spite of how the peak intake numbers compare, although at this point they would be close) it's the delivery of the power curve thats more greatly effected....and especially if we are discussing lower RPM part throttle operation....this is NEVER reflected in the dyno curve at low RPM because that is WOT comparisons....its a feel thing you have to experience to understand and its for real. So when everyone points to the rect port heads dyno curve to compare low RPM data to a cathedral its a waste of time....yes its valid info but who in their right mind actually floors the accelerator pedal at 2800 or even 3400 RPM's....you most certainly downshift to a lower gear at that point.
Old school guys who have previously owned a BBC oval port performance motor versus a rectangular port engine and had the opportunity to experience both in the same vehicle will know exactly what I'm talking about....even if the peak power numbers were close, and the track performance was close, the drivability and low RPM torque at part throttle is night and day better with the smaller high velocity oval port heads. Hell the same car felt faster driving around town even if it wasn't....
The new LS3/L92 heads are a leap forward in a big way from the older OEM cathedral heads....no doubt about it, but IMO looking at them purely from a design stand point they are not terribly efficient and leave quite a bit of room for improvement....but thats all the good news honestly. As the aftermarket continues to invest time in building clean sheet design square port heads, the performance potential of these engines will go even higher.
Im confident I could take an L92 head and make it 20 cc's smaller and improve its flow at the same time....if that was the case what do you think the outcome would be come dyno and track day? The head would be alot more efficient and the power curve would certainly reflect that. Wanna make an L92/LS3 head better....spark up the welder and/or grab a can of your favorite epoxy....make it more efficient as well as adding CFM....don't just make a big head larger in search of added CFM, but unfortunately that's not very practical and to really accomplish this you need a clean sheet design casting to work with. Its the same argument we made 7 years ago when we launched the AFR 205.....everyone scoffed at it originally....a smaller port....what were they thinking?? But a port that head 5 cc's less finished volume than a stock LS6 head (the best OEM port at the time) and flowed almost 50 more CFM's. Alot more power in a package that felt like it wanted to explode down low if you were smart enough not to over cam the car.
I'm not sure why there is so much controversy lately with cathedral and rect port LS offerings....they both have their place in the world....they both have their upsides....and they both have their downsides. Picking the right head is just as important, if not more important than picking the right cam....it just depends on what your setting out to accomplish.
Sorry for the semi-lengthy rant but it seems no matter where I turn on the Internet the same BS keeps popping up everywhere with alot of the same players stirring the pot....hell it must be the topic of twenty threads in five different sections of just this particular site right now.
Hope this helped a few of you....
Thanks,
Tony
It does in fact take a really well designed cathedral port head with a smaller cross section (and a non raised runner) to compete with the latest offering from the general which in fact has the benefits I previously mentioned to help out the airflow curve in a substantial way.
However, if are wanting to compare a smaller high efficient port design to a larger less efficient design (in spite of how the peak intake numbers compare, although at this point they would be close) it's the delivery of the power curve thats more greatly effected....and especially if we are discussing lower RPM part throttle operation....this is NEVER reflected in the dyno curve at low RPM because that is WOT comparisons....its a feel thing you have to experience to understand and its for real. So when everyone points to the rect port heads dyno curve to compare low RPM data to a cathedral its a waste of time....yes its valid info but who in their right mind actually floors the accelerator pedal at 2800 or even 3400 RPM's....you most certainly downshift to a lower gear at that point.
Old school guys who have previously owned a BBC oval port performance motor versus a rectangular port engine and had the opportunity to experience both in the same vehicle will know exactly what I'm talking about....even if the peak power numbers were close, and the track performance was close, the drivability and low RPM torque at part throttle is night and day better with the smaller high velocity oval port heads. Hell the same car felt faster driving around town even if it wasn't....
The new LS3/L92 heads are a leap forward in a big way from the older OEM cathedral heads....no doubt about it, but IMO looking at them purely from a design stand point they are not terribly efficient and leave quite a bit of room for improvement....but thats all the good news honestly. As the aftermarket continues to invest time in building clean sheet design square port heads, the performance potential of these engines will go even higher.
Im confident I could take an L92 head and make it 20 cc's smaller and improve its flow at the same time....if that was the case what do you think the outcome would be come dyno and track day? The head would be alot more efficient and the power curve would certainly reflect that. Wanna make an L92/LS3 head better....spark up the welder and/or grab a can of your favorite epoxy....make it more efficient as well as adding CFM....don't just make a big head larger in search of added CFM, but unfortunately that's not very practical and to really accomplish this you need a clean sheet design casting to work with. Its the same argument we made 7 years ago when we launched the AFR 205.....everyone scoffed at it originally....a smaller port....what were they thinking?? But a port that head 5 cc's less finished volume than a stock LS6 head (the best OEM port at the time) and flowed almost 50 more CFM's. Alot more power in a package that felt like it wanted to explode down low if you were smart enough not to over cam the car.
I'm not sure why there is so much controversy lately with cathedral and rect port LS offerings....they both have their place in the world....they both have their upsides....and they both have their downsides. Picking the right head is just as important, if not more important than picking the right cam....it just depends on what your setting out to accomplish.
Sorry for the semi-lengthy rant but it seems no matter where I turn on the Internet the same BS keeps popping up everywhere with alot of the same players stirring the pot....hell it must be the topic of twenty threads in five different sections of just this particular site right now.
Hope this helped a few of you....
Thanks,
Tony
10-31-2010 | 08:20 PM
#154
IIRC, the price of bare L92 heads 318.xx each from JEGS/Summit. Add the price of required valve springs and pushrods(Who does this swap, and keeps the stock cam?), offset intake rockers(might as well by exhaust rockers while your at it), lifters, valves, seats, locks, retainers, yada yada yada...Price isn't THAT much different.
they had them for sale for 344.50 ea assembled with springslast i checked was a month or 2 ago and the price was about to go up
EDIT now 375 each with 570 lift springs
Last edited by smok'nZ; 10-31-2010 at 08:26 PM.
11-01-2010 | 03:08 PM
#156
Mast Motorsports/Performance Induction Cathedral Port head:
Big bore, big intake runner (275cc), and big valves (2.20)
11.2:1 Compression Ratio, built by HKE. Cathedrals can make big torque and big power. Cathedrals with LARGE intake runners and intake valves can make big power. It's all about the setup and combo, just as it always has been even before Ls motors existed. I wouldn't put this head on a 346 though. It needs cubes to suck it dry.
I've seen those tests done by Vengeance and others of the ls7 head vs. TFS 235 heads, and they TFS heads won. However they used the same cam that was designed for the cathedral TFS head. It really wasn't a fair comparison imho. If funding and time allowed, it would have been nice if they maxed out the combo and cam for each head based on it's intended usage. Then a clearer picture could have been painted.
The next motor I'm building is square port, but not because the Cathedrals can't make big power. Just a setup choice in the car.
04-07-2016 | 11:53 PM
#159
TECH Addict
Joined: Sep 2010
Posts: 2,898
Likes: 467
I just want to post some of my experiences with l92's and cathedral port heads.
here are some of the combinations we have done.
6.0 gto wcch l92's ls3 intake 505 rwhp
6.2 vette wcch l92's ls3 intake 521 rwhp
416 gto va speed l92's ls3 intake 540 rwhp
427 vette wcch l92's fast 102 577 rwhp 656 fwhp
427 fbody wcch l92's fast 102 665 fwhp-not in car yet.
cathedral similar to above
6.0 gto tfs 225''s fast 90 525rwhp
416 gto tfs 235's fast 90 (a4) 505rwhp
427 gto tfs 235's fast 90 550 rwhp(a4) 654 fwhp
with that being said-the l92's have no place on a small displacement engine,especially a 4.0 bore engine. While they make pretty decent power on the smaller engine the low end sucks. The 6.2 vette actually drove really great and had excellent throttle response.
the bigger engines-416, 427, the l92's def shined on them. While we made similar power with the tfs heads, it should also be noted the cathedral's required a much larger cam. The larger cam actually sacrificed more tq down low than the larger port smaller cam did.
What it comes down to is this,every engine needs a different head. What works well on a 6.0 shouldn't and doesn't work nearly as good on a 427 and vise versa. Any good engine builder knows this. On smaller engines i will always defer to a smaller head-this is where catherdral ports shine,these engine need to make tq,always remeber you can't have hp without tq. On a larger engine 400+ with a 4.065 and larger bore, i will run a square port. On the larger engines i can sacrifice some low end for top end as usually there is too much for street cars anyway.
There are also other variables to consider too. How heavy is the car,what's it used for etc. The will determine which is better for the application. If it's something that's going to get sprayed, you can get away with a bigger port. Turbo,smaller port.
You simply cannot put a blanket statement that one type of head is better than another. Every head has it's place that it shines over the others. Otherwise everybody would only make one head at one port volume. Just remember, everything is a compromise. You have to sacrifice one thing for another when building engines.
here are some of the combinations we have done.
6.0 gto wcch l92's ls3 intake 505 rwhp
6.2 vette wcch l92's ls3 intake 521 rwhp
416 gto va speed l92's ls3 intake 540 rwhp
427 vette wcch l92's fast 102 577 rwhp 656 fwhp
427 fbody wcch l92's fast 102 665 fwhp-not in car yet.
cathedral similar to above
6.0 gto tfs 225''s fast 90 525rwhp
416 gto tfs 235's fast 90 (a4) 505rwhp
427 gto tfs 235's fast 90 550 rwhp(a4) 654 fwhp
with that being said-the l92's have no place on a small displacement engine,especially a 4.0 bore engine. While they make pretty decent power on the smaller engine the low end sucks. The 6.2 vette actually drove really great and had excellent throttle response.
the bigger engines-416, 427, the l92's def shined on them. While we made similar power with the tfs heads, it should also be noted the cathedral's required a much larger cam. The larger cam actually sacrificed more tq down low than the larger port smaller cam did.
What it comes down to is this,every engine needs a different head. What works well on a 6.0 shouldn't and doesn't work nearly as good on a 427 and vise versa. Any good engine builder knows this. On smaller engines i will always defer to a smaller head-this is where catherdral ports shine,these engine need to make tq,always remeber you can't have hp without tq. On a larger engine 400+ with a 4.065 and larger bore, i will run a square port. On the larger engines i can sacrifice some low end for top end as usually there is too much for street cars anyway.
There are also other variables to consider too. How heavy is the car,what's it used for etc. The will determine which is better for the application. If it's something that's going to get sprayed, you can get away with a bigger port. Turbo,smaller port.
You simply cannot put a blanket statement that one type of head is better than another. Every head has it's place that it shines over the others. Otherwise everybody would only make one head at one port volume. Just remember, everything is a compromise. You have to sacrifice one thing for another when building engines.
Torque low down is not that good and kind of airy and engine is not as urgent in its power delivery although it made great numbers.
I had a feeling that these heads on a 6.0 do not provide enough port velocity because the ports are so big and need more air rushing through them.
So now I am in the process of building a 408 stroker using my ls2 block. With that many cubes these heads should come to life and hopefully have high port velocity like the cathedrals. I am using a 223/231 111lsa cam utilising Comp lsl lobes.
Any thoughts?
04-08-2016 | 08:56 AM
#160
I have to agree with this post as i have an ls2 6.0 with l92 cnc heads and a fast 102mm intake and since fitting these the engine does not feel as quick.
Torque low down is not that good and kind of airy and engine is not as urgent in its power delivery although it made great numbers.
I had a feeling that these heads on a 6.0 do not provide enough port velocity because the ports are so big and need more air rushing through them.
So now I am in the process of building a 408 stroker using my ls2 block. With that many cubes these heads should come to life and hopefully have high port velocity like the cathedrals. I am using a 223/231 111lsa cam utilising Comp lsl lobes.
Any thoughts?
Torque low down is not that good and kind of airy and engine is not as urgent in its power delivery although it made great numbers.
I had a feeling that these heads on a 6.0 do not provide enough port velocity because the ports are so big and need more air rushing through them.
So now I am in the process of building a 408 stroker using my ls2 block. With that many cubes these heads should come to life and hopefully have high port velocity like the cathedrals. I am using a 223/231 111lsa cam utilising Comp lsl lobes.
Any thoughts?