Ls3 bottom end w/243 head question
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Teching In
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Ls3 bottom end w/243 head question I have an 04 CTS-V I recently scored a LS3 short block. I want to put my 243's from my LS6 on the LS3. My heads have been decked 20 thousandths, stock head gaskets. I have a TSP 228R cam does anyone have an idea where my compression ratio would be?
I calculate closer to 11.3 static CR. The cam overlap is a big factor in calculating dynamic CR. If this is with a stock cam, you might be on the edge with pump gas unless you use 93 octane.
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Teching In
Joined: Jun 2005
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From: Little Rock, AR
I have a LS3 bottom end and 243 heads with a slightly larger cam. my heads were decked .025 and to get compression around 11.6 I had to get a custom cometic gasket at .070. I think you will be fine with what you have.
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What's wrong with cathedral port heads?
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Joined: Nov 2005
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From: NY
found this thread doing a compression ratio search. having an engine built right now for my project car and i was discussinf CR tonight with my guy. says my setup is 11.5:1 instead of the 12.5:1 i initially though it was going to be. I was told that the 11.5 is better given i will be using this car primarily for the street and if the wife god forbid doesn't catch the idiot attendants (yes, in NJ you cannot pump your own gas....very lame) i would be in a better position if i didn't realize and started beating on it. I was also told it would be max 20hp difference in the higher CR (from 11.5-12.5) given the variables . when it is tuned i will be tuning it on WaWa 92 octane as another failsafe just in case. So i will be able to tell you how running on less than 93oct ends up. I will also be tuning for 100 octane just to compare differences for future reference/builds. it really pays to have a good friend with a mustang dyno lol.
if this were a pure hobby/show/track car i would've gone ridiculous cam (if i kept it NA like i did now).
In other words, you're more than fine with the 11.5-6:1 lol
nothing, unless you're going over 400cu. that's where the L92's really pick up steam (from what i've heard, wtf do i know? lol)
im sure there's threads on this forum but here's a quick interesting read
http://www.yellowbullet.com/forum/sh...=473542&page=2
if this were a pure hobby/show/track car i would've gone ridiculous cam (if i kept it NA like i did now).
In other words, you're more than fine with the 11.5-6:1 lol
What's wrong with cathedral port heads?
im sure there's threads on this forum but here's a quick interesting read
http://www.yellowbullet.com/forum/sh...=473542&page=2
LS3/L92 heads will flow way more then the 243's i hav a set of L92 heads for sale. the only difference between the LS3 an L92 is the intake valve is hollow stem in the LS3 heads and solid in the L92's
I'll be doing the same thing on my 418 ls3 motor. AI 243 heads and Fast92/92 combo with a texas giant cam. Not optimal heads but since its the setup I have its what I'm going with. Once I get it broken in and tuned well I'll post up some dyno numbers. I wont have any track numbers since there isnt one here....If it makes 500/500 through my 4k stall I'd be extremely impressed!
