View Poll Results: PRC LS6 & MS4 or PRC 5.3 & MS3
PRC LS6 & MS4
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25
55.56%
PRC 5.3 2.5 & MS3
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20
44.44%
Voters: 45. You may not vote on this poll
PRC LS6 & MS4 or PRC 5.3s & MS3
#21
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Are you saying that the LS6 heads are less efficient than the 5.3's?
#25
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I have been contemplating this exact same question for the exact same reasons. Here is what I am going with;
I will be opting for the MS3 and the 5.3 stage 2.5 heads. Given that the heads will out perform the stage 1 LS6 heads, but also taking in consideration that the MS4 will make a little more power than the MS3, you are talking maybe 5 RWHP difference from the two (TSP agrees with this estimate). It just makes more sense to me that the drivability being better on the MS3, and the slightly less peaky power curve is all the more reason to choose it over the MS4 combo.
If you go the flycut piston route, then take advantage and just go all out on the heads, and go with the MS4. But it sounds like you are in the exact same boat as me, and want to avoid flycutting the pistons.
As for the springs, I wouldn't worry about that either as the dual PRC springs that come with either of the kits will well support the high RPM abuse you will put them through with either cam.
I will be opting for the MS3 and the 5.3 stage 2.5 heads. Given that the heads will out perform the stage 1 LS6 heads, but also taking in consideration that the MS4 will make a little more power than the MS3, you are talking maybe 5 RWHP difference from the two (TSP agrees with this estimate). It just makes more sense to me that the drivability being better on the MS3, and the slightly less peaky power curve is all the more reason to choose it over the MS4 combo.
If you go the flycut piston route, then take advantage and just go all out on the heads, and go with the MS4. But it sounds like you are in the exact same boat as me, and want to avoid flycutting the pistons.
As for the springs, I wouldn't worry about that either as the dual PRC springs that come with either of the kits will well support the high RPM abuse you will put them through with either cam.
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Im actually going with a totally different setup now. I talked to John at TSP and im going to go with the 2.5 Ls6/Trak cam. I have seen ungodly dyno sheets from this setup. It also makes huge torque. I will have the heads milled and i also dont have to flycut.
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This is a dyno sheet i found on the site. I found this and this changed my mind.
https://ls1tech.com/forums/generation-iii-internal-engine/758749-patrick-g-tuned-my-trak-cammed-prc-ls6-2-5-s-car-results-inside.html
https://ls1tech.com/forums/generation-iii-internal-engine/758749-patrick-g-tuned-my-trak-cammed-prc-ls6-2-5-s-car-results-inside.html
#29
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This is a dyno sheet i found on the site. I found this and this changed my mind.
https://ls1tech.com/forums/showthread.php?t=758749
https://ls1tech.com/forums/showthread.php?t=758749
One guy stated it had great mid range, but the graph shows the same low numbers in the low and mid range, and the power not coming on until 4500 or so (which again is almost the same as you would find with the MS4 or MS3).
It seems pretty much like the same as either the MS3, or MS4 cam I guess is what I am saying.
Last edited by CALL911; 01-07-2008 at 05:41 PM.
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I guess it does seem to make a little lower peaking torque, but keep in mind all of this was with the stage 2.5 LS6 heads vs the stage 2.5 5.3 heads (huge difference right there). Take the heads into account for everything, and I'll bet you'd see similar results with either the MS3 or the MS4, as the huge cams really need to breath, so anything you do to help that (heads and intake) is going to help exponentially.
You mentioned that there are tons of threads out there of dyno #'s for the MS3 and the stage 2.5 PRC 5.3 heads. Do you have any links of them? I am curious to see someone's MS3, 5.3, 2.5 heads combo dyno graph compared to the trak cam.
You mentioned that there are tons of threads out there of dyno #'s for the MS3 and the stage 2.5 PRC 5.3 heads. Do you have any links of them? I am curious to see someone's MS3, 5.3, 2.5 heads combo dyno graph compared to the trak cam.
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I have been looking at a lot of different setups....but not sure what im going to do. I will be giving John another call tomorrow before i decide. I am either going with the milled 2.5 Ls6s or the milled 5.3s. Im not sure which would produce more hp. Since the Ls6s can take a bigger cam, will it produce more hp?
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I have been looking at a lot of different setups....but not sure what im going to do. I will be giving John another call tomorrow before i decide. I am either going with the milled 2.5 Ls6s or the milled 5.3s. Im not sure which would produce more hp. Since the Ls6s can take a bigger cam, will it produce more hp?
As for me, I am looking at driveability (to an extent), as well as most cost effective power which would keep me from flycutting which would also keep me from milling the heads.
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If i went with the MS3 and the milled 2.5 Ls6s....i shouldnt have to flycut should i? I know you can have the heads milled and still fit the Trak with no problems.