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Boost/ Power limits of ls7 and l92 heads

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Old Mar 17, 2010 | 09:59 PM
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Default Boost/ Power limits of ls7 and l92 heads

Just as the topic reads, Im just wanting to know how much boost these heads can hold, more for my own edification than anything. All things considered, after some conversations with some very knowledgeable members here, the savings aren't worth it by the time its all said and done. However, I may just re-assess my goals if these can come close enough. Basically, I want to have the potential to run up to 18 lbs, but 15-16 would probably be good enough, if they will hold that.
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Old Mar 17, 2010 | 10:30 PM
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stock ls7?


whats the compression ratio going to be with the l92 heads?

will these heads be oringed?

head studs would be a good idea of course

as long as its not high compression and you run studs you should be fine,you can oring them to help if your worried about it
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Old Mar 17, 2010 | 11:51 PM
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Basically, I want to have the potential to run up to 18 lbs, but 15-16 would probably be good enough, if they will hold that.
You need to post more about the setup.
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Old Mar 18, 2010 | 05:55 PM
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Well basically I want to know how far the stock ls7 and l92 casting will go in terms of forced induction. I am wanting to build a 427-454 using the LSX block, only because its my understanding that it is my best option for the $ and for the potential to upgrade cubes with the future rebuilds. I am open to using a stock block that would hold the power also. It is also my understanding that 8:5:1 to 9:0:1 is what the c/r should be with twin turbos. Im thinking 76mms w/ .46-.57 a/r would get it down. I only want to run pump gas, and I want to make as much power as I can on pump gas. Again, my understanding is that 1000-1200 rwhp is possible to do quasi reliably on 93 and less than 18lbs. I have been told that l92s and ls7s will lift/leak past 14lbs. I would be running upgraded springs/cam obviously. I am open to all info, I have been told that I need to buy aftermarket casting heads when the time comes.
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Old Mar 18, 2010 | 06:03 PM
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And Yes I am certainly willing to have it o-ringed. But I would guess that if I need to buy aftermarket heads then o-ringing might not be necessary
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Old Mar 18, 2010 | 06:09 PM
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Also now with o-ringing. What about the receiver ring in the head?

and now I just found something called pyramid rings. An ls1 user seems to have crazy results.... http://forums.corvetteforum.com/c5-f...questions.html
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Old Mar 18, 2010 | 08:26 PM
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Yes there is a thread here on tech about the pyramid ringing but promblem is findiing a mechinest that knows how to install them. I also have a set of l92s that i plan on pushing well above 14-15lbs that i need to get o-ringed or pyramid ringed.
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Old Mar 18, 2010 | 10:15 PM
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If you are going with the LSX block, then I would recommend going with aftermarket heads as well for boost. Might as well put those extra head studs to use.
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Old Mar 19, 2010 | 12:38 PM
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Well thats also part of the question. Is there a stock block at that could 1) have a large enough bore to run these heads and 2) make 427 cubes and 3) hold that much power?
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Old Mar 19, 2010 | 01:09 PM
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6.0 block will take those heads and power but you will have to do sleeves to get a 427
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Old Mar 19, 2010 | 02:39 PM
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Thats why I was leaning towards the LSX bowtie, because by the time you do all that to a production block, its cheaper

Do you know about the 6.2 block? How will it fair with a stroker kit?
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Old Mar 19, 2010 | 03:30 PM
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On the 427 ls3 it is not a good idea to put it under boost. The 416-418 would be a better choice.

Save youself the headache and save up for a set of All-pro's or a set of ETP's(Cary's Induction). They have the deck you would want for boost. By the time you get the L92's done up, change the springs and valves, O-ring them and all, you are only a little bit short of a set of All Pro's.

If you are willing to spend the cash on an LSX block and put good internals to handle 1000hp why skimp on the heads?
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Old Mar 19, 2010 | 04:00 PM
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Well I just want to know what my options are. If an l92 engine w/ a stroker kit could get it done... it might be enough for me and save a couple thousand. But as well all know, what is a few extra thousand dollars in the long run... nothing. But Im just learning, Ive been a ford guy for years and im familiar with ls stuff, but now I am getting closer to really starting a drag build and the plan is to go ford tough with chevy stuff.
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Old Mar 19, 2010 | 06:24 PM
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For what you are trying to do, don't waste any money on an l92 for boost. An ls7 head is a little better but an aftermarket casting is so much better with having a thicker deck and the option of 6 bolt heads on an lsx block.

If it were me I would be looking at a set of All Pro's.
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Old Mar 19, 2010 | 07:35 PM
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for a reliable 1000+ hp you really need a good aftermarket head.While a stock head will work thru dyno pulls you will have issues.We've had the best luck with the Performance Inductions heads on high hp forced induction builds.My philosophy is to build it right once instead of 3 times the wrong way
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