HOT ROD head comparison (cathedrial vs square)
#42
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I though it was a good article & it was really cool to see all the heads flowed on the same bench & the same day.
I would have like to see the PRC 237 heads pulled a few hundred more RPM. You can see they're the only heads that didn't back up on the flow bench & hadn't peaked when the dyno pulls were stopped. The test was very interesting, but didn't completely show the power potential of the PRC 237 heads...
Porting stock heads for $1340+the cost of castings puts it really close in price to most of these nice aftermarket casting cylinder heads. while $1340 sounds cheap it's actually not that much cheaper when you add in a good set of LS6 cores (typically $500 for used on ebay)
I also noticed some of the vendors shipped with chambers smaller than requested. While that doesn't make a lot of difference, it makes a few hp & that's what we're talking about in differences here....
I would have like to see the PRC 237 heads pulled a few hundred more RPM. You can see they're the only heads that didn't back up on the flow bench & hadn't peaked when the dyno pulls were stopped. The test was very interesting, but didn't completely show the power potential of the PRC 237 heads...
Porting stock heads for $1340+the cost of castings puts it really close in price to most of these nice aftermarket casting cylinder heads. while $1340 sounds cheap it's actually not that much cheaper when you add in a good set of LS6 cores (typically $500 for used on ebay)
I also noticed some of the vendors shipped with chambers smaller than requested. While that doesn't make a lot of difference, it makes a few hp & that's what we're talking about in differences here....
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Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
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Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
#43
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I received the test set of heads back from Hot Rod already guys, if anyone is looking for a good deal on a slightly used set of PRC 237s give us a call. I'll make someone a pretty good deal.
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Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
#44
The other thing that should be mentioned Jason is with a 243 casting people can re-use the stock rockers, that is not an option with some of the after market castings so in most cases your looking at a minimum of an additional $500 on top of the cost of the heads.
#45
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But that's not the case on ALL the aftermarket castings
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#47
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They were milled to what we were told would be the standard for the test.
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#48
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I understand that for the sake of an apples to apples comparison that using the same cam makes sense, but I can't help but wonder if the benefits of those LS3 heads were masked somewhat by the fact that they aren't going to perform at their best with the same cam that the cathedral style heads would.
#49
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I understand that for the sake of an apples to apples comparison that using the same cam makes sense, but I can't help but wonder if the benefits of those LS3 heads were masked somewhat by the fact that they aren't going to perform at their best with the same cam that the cathedral style heads would.
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#50
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Oh, so each company was contacted and requested a specific head for testing? That's different than a blind comparison.
Before anyone jumps down my throat about sending or not sending ringers, get real. If a magazine contacts you and asks you to send one of your products for a comparison test, and you DON'T send a fully optimized, tested, optimum product, then you need your head examined.
That leads to the question of how much was done to get to the magazine level.
Before anyone jumps down my throat about sending or not sending ringers, get real. If a magazine contacts you and asks you to send one of your products for a comparison test, and you DON'T send a fully optimized, tested, optimum product, then you need your head examined.
That leads to the question of how much was done to get to the magazine level.
#51
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the procomp heads did pretty good too,i didn't even know they made heads for the LS engine family.in the price is off the chain,all i've ever heard of them was in a mag when they used a set on a 496 bbc.has any used these on LS1TECh?
#52
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Great article ... .... I got my issue of HRM Tuesday and have read the article at least 4 times now...seems like a pretty fair test of the different heads...thanks David for the interesting data to compare these heads...I can't wait to see the part two on the retangular port heads..Hot Rod is still the best auto mag on the market .... I have been reading it religiously for over 50 years...
#54
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Ringers are always a possibility with these tests. I'd look really close at all the heads, most are off cnc machines so they're most likely not crazy ringers... If there were hand finished heads I'd be really wondering if they're consistant with what they ship.
Did anyone notice if all the heads were cnc ported intakes? I'll checkout the pics closer Monday to see.
Did anyone notice if all the heads were cnc ported intakes? I'll checkout the pics closer Monday to see.
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Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
#56
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I thought I would create a spreadsheet for the results, I should probably follow this up with one of avg coefficient of discharge based on valve diameter, flow and port volume. That would probably explain the results a little better, especially when you consider the heads with the smallest port volume (Procomp at 219cc) made the most HP and the some of the largest heads made the least (Dart 249cc and World 255cc)
I was surprised that the TFS 235 heads had the highest average torque and the highest average horsepower, but didn't have the highest peak torque or peak horsepower.
Something to note, the CNC program for the TEA LS6 heads is all new for 2010, it was in the works for a couple years.
I put the cost per horsepower gained, which made the most sense to me.
I was surprised that the TFS 235 heads had the highest average torque and the highest average horsepower, but didn't have the highest peak torque or peak horsepower.
Something to note, the CNC program for the TEA LS6 heads is all new for 2010, it was in the works for a couple years.
I put the cost per horsepower gained, which made the most sense to me.
Last edited by Brian Tooley Racing; 10-24-2010 at 09:50 PM.
#57
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I was surprised that the TFS 235 heads had the highest average torque and the highest average horsepower, but didn't have the highest peak torque or peak horsepower.
Something to note, the CNC program for the TEA LS6 heads is all new for 2010, it was in the works for a couple years.
Something to note, the CNC program for the TEA LS6 heads is all new for 2010, it was in the works for a couple years.
Are all of the stage 243 heads new for 2010 or just the stage 2? Originally I was considering the AFR 230 v2 or 245 heads for a future 408ci but now I think saving $1000 with TEA ls6 heads would be better after this test. Would you say the stage 2.5/3 would do better or would the bigger valves and runners be less efficient for a 408ci but better suited for a 427ci and up.
#58
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Are all of the stage 243 heads new for 2010 or just the stage 2? Originally I was considering the AFR 230 v2 or 245 heads for a future 408ci but now I think saving $1000 with TEA ls6 heads would be better after this test. Would you say the stage 2.5/3 would do better or would the bigger valves and runners be less efficient for a 408ci but better suited for a 427ci and up.
The Stg 3 is bigger, and requires changing the seats on intake and exhaust for the 2.08"/1.60" valves, which adds considerable cost to the total price and is not where I would spend my money.
Something else to note about the TEA LS6 heads, back in 2004 ECS made 600 rwhp with the Stg 3 LS6 heads on a hyd roller cam 440 with a Fast intake. People called BS on it, but the car ran 138 mph in the 1/4 on motor, so the potential of these heads are there, but I wouldn't spend a ton of money on stock castings.
For a 427 the TFS 235's/245's with a proper port matched Fast 102 (which means the heads HAVE to be ground on) would be a good choice. The Mast LS3 heads with the same work on a Fast 102 would also be a good consideration.
For a 408, I would also consider the hp winners of this article, with proper cam timing the torque could be brought up, and proper port matching would probably help these heads as well.
Last edited by Brian Tooley Racing; 10-24-2010 at 10:17 PM.
#59
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Glad you guys liked the story. I did, too, and Richard Holdener killed himself doing it. And I have part 2 on my desktop as I type this...it's the test of all the rec-port heads. The first test was all cathedral-ports except the Mast units. I was stunned how the power output changed almost not at all regardless of port cross section, cc, or flow.
BTW, timing sweeps were executed on each head, and they all seemed to want 30.
The next story on the rec ports is with a 468ci motor.
BTW, timing sweeps were executed on each head, and they all seemed to want 30.
The next story on the rec ports is with a 468ci motor.
#60
I thought I would create a spreadsheet for the results, I should probably follow this up with one of avg coefficient of discharge based on valve diameter, flow and port volume. That would probably explain the results a little better, especially when you consider the heads with the smallest port volume (Procomp at 219cc) made the most HP and the some of the largest heads made the least (Dart 249cc and World 255cc)
I was surprised that the TFS 235 heads had the highest average torque and the highest average horsepower, but didn't have the highest peak torque or peak horsepower.
Something to note, the CNC program for the TEA LS6 heads is all new for 2010, it was in the works for a couple years.
I put the cost per horsepower gained, which made the most sense to me.
I was surprised that the TFS 235 heads had the highest average torque and the highest average horsepower, but didn't have the highest peak torque or peak horsepower.
Something to note, the CNC program for the TEA LS6 heads is all new for 2010, it was in the works for a couple years.
I put the cost per horsepower gained, which made the most sense to me.