Cathedral or square port heads?
10-25-2014, 03:43 AM
#1
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Cathedral or square port heads? I know this probably has been discussed before, but has anyone done a back to back dyno comparison for cathedral port heads against square port heads, iam mainly interested in the torque curve difference below 4000rpm's, TIA
10-25-2014, 08:59 AM
#3
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I have did my own personal comparison on this. It's very very interesting. On a 454 Ci motor built by LME using LS7 heads the engine made 550 tq at 4000 rpm... Tooley also did a 454 ci with 245 TFS at 4000 rpm the motor cleared 600 ft lbs of torque and the motor never dropped below 570 ft lbs. Lme 454 had a tad bit more compression also, both motors had a 102mm fast intake, however LME 454 did make 600 ft lbs but at a later 5400 rpm. And in the horsepower department it was only 7 horsepower difference between the two. 705 horses (TFS)to LME LS7 heads (712hp)
10-25-2014, 09:42 AM
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I have did my own personal comparison on this. It's very very interesting. On a 454 Ci motor built by LME using LS7 heads the engine made 550 tq at 4000 rpm... Tooley also did a 454 ci with 245 TFS at 4000 rpm the motor cleared 600 ft lbs of torque and the motor never dropped below 570 ft lbs. Lme 454 had a tad bit more compression also, both motors had a 102mm fast intake, however LME 454 did make 600 ft lbs but at a later 5400 rpm. And in the horsepower department it was only 7 horsepower difference between the two. 705 horses (TFS)to LME LS7 heads (712hp)
10-25-2014, 11:45 AM
#5
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Just imagine dumping the clutch on the TFS motor at 4000 rpm!! Hello neck brace lol
10-25-2014, 01:51 PM
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10-25-2014, 10:39 PM
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No doubt about that bro ^^
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10-26-2014, 12:32 AM
#9
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What heads ?
10-26-2014, 01:56 AM
#11
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That's awesome!! Still a cathedral head tho :-)
10-26-2014, 08:49 AM
#13
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I have studied this topic too..... The CAM SELECTION is so so critical on a 6.0 with LS3 heads. I got this in my car right now. We'll it's a bored LQ motor with a Tooley 229/244 cam. I won't know what it put down till Friday. However my best car guy friend have a LQ9 motor with LS3 heads up top and he puts down 475rwhp ( we both have M6 camaros). His cam is a 228/242. Most 243 headed 6.0 motors I seen put down a average 430.... 450 been the highest I've seen n/a. It's a very hard decision here...... only way I would do a 243 head if it's been ccompleted ported by somebody like Chris Frank but then you spend money. If you look at Brian Tooley stage II LS3 cam 225/238 I believe that cam pumped out 470 rwhp out a 2011 camaro. After all its only like 12 cubic inches difference between a 6.0 motor (364ci) and a 6.2 (376ci).
10-26-2014, 08:52 AM
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Hold just a sec there... First off if cathedral ports were better they would be fabricated by GM in the ls3 lsa ls9 and ls7 motors but they are not because their design is inferior plain and simple.
It is true some well research cathedral port heads exist and work well and so does small block Chevy motors but that does not cover the fact that they are obsolete on both counts.
The state of the art ls3 and ls7 heads are superior in every way if you are willing to look at the facts.
The GM ls7 head is a poor design head when compare to aftermarket counterparts by a factor of 25% in my personal book so is not a level plying field when comparing the best of cathedral ports heads to GM ls7 heads port designs.
When the comparison is between the best cathedral port heads against the best square port heads of the same cubic inch displacement then and only then will you have a true and equal comparison and correct results and the real story as to which head port design produce the better head.
If cathedral ports worked better all the builds for max power would be employing them.
It is true some well research cathedral port heads exist and work well and so does small block Chevy motors but that does not cover the fact that they are obsolete on both counts.
The state of the art ls3 and ls7 heads are superior in every way if you are willing to look at the facts.
The GM ls7 head is a poor design head when compare to aftermarket counterparts by a factor of 25% in my personal book so is not a level plying field when comparing the best of cathedral ports heads to GM ls7 heads port designs.
When the comparison is between the best cathedral port heads against the best square port heads of the same cubic inch displacement then and only then will you have a true and equal comparison and correct results and the real story as to which head port design produce the better head.
If cathedral ports worked better all the builds for max power would be employing them.
10-26-2014, 09:21 AM
#15
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First off if cathedral ports were better they would be fabricated by GM in the ls3 lsa ls9 and ls7 motors but they are not because their design is inferior plain and simple.
It is true some well research cathedral port heads exist and work well and so does small block Chevy motors but that does not cover the fact that they are obsolete on both counts.
The state of the art ls3 and ls7 heads are superior in every way if you are willing to look at the facts.
The GM ls7 head is a poor design head when compare to aftermarket counterparts by a factor of 25% in my personal book so is not a level plying field when comparing the best of cathedral ports heads to GM ls7 heads port designs.
When the comparison is between the best cathedral port heads against the best square port heads of the same cubic inch displacement then and only then will you have a true and equal comparison and correct results and the real story as to which head port design produce the better head.
If cathedral ports worked better all the builds for max power would be employing them.
It is true some well research cathedral port heads exist and work well and so does small block Chevy motors but that does not cover the fact that they are obsolete on both counts.
The state of the art ls3 and ls7 heads are superior in every way if you are willing to look at the facts.
The GM ls7 head is a poor design head when compare to aftermarket counterparts by a factor of 25% in my personal book so is not a level plying field when comparing the best of cathedral ports heads to GM ls7 heads port designs.
When the comparison is between the best cathedral port heads against the best square port heads of the same cubic inch displacement then and only then will you have a true and equal comparison and correct results and the real story as to which head port design produce the better head.
If cathedral ports worked better all the builds for max power would be employing them.
10-26-2014, 10:09 AM
#16
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I agree with you on that but the OP mentioned " power under the curve" or or 4000 rpm which is midrange. If i was go build a all out 13:1 race gas car I would skip right the LS7 head factory* and jump right into a Brodix LS7 head cause you go spend moretime at 8000 plus rpm anyway and you'll probably have a 5000 rpm stall. Big square port heads are mostly 270 or bigger on the intake runner which also goes back to what I said about the high rpm. The larger the cc is on the head the more I'll turn the engine om the strip. On a street car cathedral ports really tend to shine on pump gas builds and really put down some mean *** track numbers. For instance .... I know a guy that have a 6 speed all motor street car (2000 Z28). Car has no weight reduction at all matter of the fact it weighs 3750. Combo in the car is plain and simple. Afr 205 heads ported by Mamo with a fast 92mm to match. 12 bolt with 3.90 gears. LQ block 402 ci. Ftp lid. Edelbrock headers with SLP exhaust. Monster stage 4 clutch. On a 17 inch tire the Z blasted the strip at 10.80 @ 129 mph pass/ 1.59 60ft on a hoosier DR!! She even pulled the 17 inch C5 rims off the ground. Just think if it had a full slick on the car. Midrange power is insane. How many full interior cars you see drive to the track run 6s n/a in the 1/8 mile with a 6 speed with the spare tire and Jack in the trunk and drive back home with the a/c blasting? Not many at all.
10-26-2014, 10:44 AM
#17
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10-26-2014, 12:01 PM
#19
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If you can go with a set of aftermarket heads such as afr or tfs I would aim for that
10-26-2014, 09:19 PM
#20
The rectangular port LS3 heads can flow over 300cfm straight from the factory. The cathedral port cant come close to that.
I thought I did read somewhere that the cathedral port heads were better at generating air velocity at a lower RPM, can anyone validate that?
I thought I did read somewhere that the cathedral port heads were better at generating air velocity at a lower RPM, can anyone validate that?