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Square port vs Catherdral for boost?

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Old Dec 29, 2010 | 09:57 PM
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Default Square port vs Catherdral for boost?

I've noticed a trend that most of the heavy hitter are switching over to square port (LS7/LS3) style heads over cathedral. Is there any reason for this? Does one have a large advantage over the other?
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Old Dec 29, 2010 | 10:22 PM
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I say smaller valves for turbo's with higher back pressure (1.5:1 or more exhaust to intake), bigger valves for turbo's with less back pressure (ideally 1:1)
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Old Dec 30, 2010 | 06:52 AM
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I'm staying cathedral for next year...
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Old Dec 30, 2010 | 07:32 AM
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they flow more air which equals more power at lower boost levels.
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Old Dec 30, 2010 | 07:54 PM
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Originally Posted by Shawn @ VA Speed
they flow more air which equals more power at lower boost levels.
I can't really see an upside to square ports or a downside to cathedral ports...
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Old Dec 31, 2010 | 12:06 AM
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Originally Posted by Lythropus
I can't really see an upside to square ports or a downside to cathedral ports...
The fastest hydraulic roller cammed turbo setup had TFS 245 cathedral heads, Mark Koehler running 7.30's @ 192.

One of his Ohio Boys teamates ran about the same times with All Pro square port heads and a solid roller cam.

The three most important things to making anything fast is combination, combination and combination.

Well, there may be a forth thing, COMBINATION!
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Old Dec 31, 2010 | 06:57 AM
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Both cylinder head types work well when boosted. Most times the cylinder head is made much bigger than it needs to be because cylinder heads designed for racing are normally designed around moving the most air in and out of NA engines. Valve size and placement in a turbo engine are different than the NA stuff, but all will produce great power if the head gaskets stay sealed!

Kurt
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Old Dec 31, 2010 | 10:59 AM
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Originally Posted by Brian Tooley
The three most important things to making anything fast is combination, combination and combination.

Well, there may be a forth thing, COMBINATION!
Brian,
So what exactly are you tring to say?


LOL
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Old Dec 31, 2010 | 12:24 PM
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ls3,l92,ls9,ls7 will not stay at level and will cause water push or lifting ,i mean at high boost .I have a set of l92 heads and i switched to Eledrbrock 245cc ported by Wcch
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Old Dec 31, 2010 | 12:55 PM
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Originally Posted by 427
Both cylinder head types work well when boosted. Most times the cylinder head is made much bigger than it needs to be because cylinder heads designed for racing are normally designed around moving the most air in and out of NA engines. Valve size and placement in a turbo engine are different than the NA stuff, but all will produce great power if the head gaskets stay sealed!

Kurt
Seems that finding a head that delivers sufficient flow to make the power hasn't really been an issue. The issues have more to do with sealing the deck to the heads and the mains moving around.
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Old Dec 31, 2010 | 01:39 PM
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Just got some 265 ETP cathedral port heads setup for a solid roller, I believe I'm going solid roller rather than converting these beautiful heads to hydraulic... something different to try, though we won't spin much past 7750...
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Old Dec 31, 2010 | 02:05 PM
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Originally Posted by 98Z28CobraKiller
Seems that finding a head that delivers sufficient flow to make the power hasn't really been an issue. The issues have more to do with sealing the deck to the heads and the mains moving around.
no you're right making power isn't an issue. We made 1800 with some old ETP 225's. but the better the head flows the easier is it to make power-no matter what anybody says.

head gasket sealing isn't an issue either,even though alot of people seem to have issues. 1800 hp on 4 bolt heads and well over 2000 with 6 bolt with no gasket issues.We actually break the blocks first.

The mains have been an issue in the past, but we've figures out that problem as well.

If we can get some blocks that will hold the power we will be good to go. Hopefully the RHS will handle some power. We'll see shortly.
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Old Dec 31, 2010 | 02:31 PM
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Originally Posted by Shawn @ VA Speed
If we can get some blocks that will hold the power we will be good to go.
Soon everyone making big boy power will be running a billet block...

Seems like the only safe block to run at super high hp levels AND that doesn't cost a few organs is an RHS.

Whats the next thing to let go then after you have the heads, mains, and block at the "best" it could potentially be with what technology is available?
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Old Jan 10, 2011 | 12:16 PM
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So whats the conclusion? That it does not matter what head you have, they both work great? And whatever combo you go with they will work no better than the other if both head designs are properly matched with a good combo?
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Old Jan 10, 2011 | 02:00 PM
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If you are running 1800hp plus (200mph) in the drag type car the head needs to seal well and be durable. The better it flows the easier it will be to make the power, but most times budget dictates the cylinder heads. We have seen a few sets of canted heads used with no conclusive results, but they will need time to figure out what they want before we see the full potential. Right now in the high power stuff I work with, most of our effort has been durability and consistant performance. Most of my customers are looking to win races rather than set records, that requires many consistant runs that are hopefully fast also!!

Kurt
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Old Aug 14, 2013 | 07:30 PM
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bump
was wondering if anything has changed in the last couple years now that more people are running square ports
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Old Aug 14, 2013 | 07:45 PM
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combo depends on end goal or budget.
either one gets it done, jy build or aftermarket block and heads.
gotta figure out how much you want to drop, usually results how fasr u go.
i have set of lsa heads. that i believe will hold my 800rwhp.goal.reliably.
but current build has been reliable for many years w 317 cathedrals.
rectangle ports are alot more common now and outflow any cathedrals stock to stock as is. i would prolly have to push my engine harder by using stock 317 over the lsa.
its all relative.
im leaning alot more to rectangle ports now.
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Old Aug 15, 2013 | 06:24 AM
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I have always ran cathedral ports in the past and have always been impressed by them but this time around I am going to try the square ports and see what I can do.
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