LT1-LT4 Modifications 1993-97 Gen II Small Block V8

p2v clearance question

Old Mar 8, 2011 | 08:09 PM
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Default p2v clearance question

I am in the process of assembling my lt1 with new bearings rings stock pistons and rods with new arp rod bolts.

the cam that is in it is a 242 242 572 572 112 solid roller, Right now the mockup heads are stock, the other set are heading out to get ported. I am wondering if i need to worry about p2v clearance, I dont have a test spring to check it right now, I will get one if needed. the block is stock deck height and the gaskets i have are felpro stock replacements, the heads have been checked out before and do not need milling.

thanks in advance
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Old Mar 8, 2011 | 09:29 PM
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if your worried clay test it.
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Old Mar 8, 2011 | 09:41 PM
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clay testing it is what i was gonna do if it is a possibility of interference, I am just wondering if the cam is big enough to need to worry about it
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Old Mar 8, 2011 | 10:04 PM
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that big on a 112... shouldn't have any issues. the real issue here is the single pattern cam
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Old Mar 8, 2011 | 10:10 PM
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how big/what are the single pattern issues, i know that typically lt1 and sbc cams are split duration cams but I am unsure why
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Old Mar 8, 2011 | 11:19 PM
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they just don't work that well with the ltx platform. It doesn't have so much to do with I/E flow, it has to do with the intake design and what it needs to work as good as it can. Not that your cam won't work, I just see big-ish duration, wide-ish lobe separation, and not enough overlap.
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Old Mar 9, 2011 | 01:44 AM
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I'm not sure what you'll be running for heads, or how high you plan on spinning the motor, or what the rest of your combination will be, but strictly looking at the cam, I'd go a little less duration on the intake side, and bring your LSA closer to a 108 area.

As for your actual question, I'd do (I personally always do it) what AC said and clay test it.

Last edited by 93Z2871805; Mar 9, 2011 at 01:52 AM.
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Old Mar 9, 2011 | 01:49 AM
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I already have the cam, its gonna have longtube headers, ls1 air intake, 3200 stall and i gotta get gears, cause i sold my 4.11 axle to get the motor, probably going 3.73 next time.

gonna spin it as high as it needs
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Old Mar 9, 2011 | 01:51 AM
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would doing 1.5 on the intake and 1.6 rockers on the exhaust help this cam out? btw the lift is for 1.5 rockers
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Old Mar 9, 2011 | 02:03 AM
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The rockers would only really change the lift (with a very small influence on the duration) and pop the valve off the seat a little quicker (speed wise, not position wise). The actual concern here is the duration (more on the intake side) and the overlap that you wont have alot of due to your lobe separation angle being wide.
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Old Mar 9, 2011 | 02:18 AM
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what about advancing/retarding the cam, would that make any difference? sorry about the questions, I dont know all that much when it comes to cams. gotta learn somehow right
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Old Mar 9, 2011 | 02:20 AM
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i know that doing that wolnt change the cam specs, or anything, but what about power wise? I do have some offset cam bushings to do that if its needed, and the cam card as well
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Old Mar 9, 2011 | 02:22 AM
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What's your intake centerline?
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Old Mar 9, 2011 | 02:29 AM
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And static compression ratio?
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Old Mar 9, 2011 | 02:34 AM
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lol i spoke too soon, i cant find it now, i just moved a few weeks ago and cant remember where i saw it. i will look for it tomorrow and post up
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Old Mar 9, 2011 | 02:47 AM
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Well, depending on your heads, if your ICL is closer to 106, I see it making good torque down low and falling off around 5.5k. If it's closer to 110, I see it making good midrange between 4.5k-6k. The problem will be either nothing to carry it into the higher rpms, or a very narrow power band. You could go with a 1.6 rocker on the exhaust and -2* cam timing to try to push the power band higher.
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Old Mar 9, 2011 | 03:06 AM
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on the scr, I havent gotten around to calculating that yet, it will be stock pistons stock deck height and stock head cc chambers, as well as a fel pro stock replacement gasket (i can get the part number if needed)
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Old Mar 9, 2011 | 08:31 AM
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Originally Posted by 93Z2871805
Well, depending on your heads, if your ICL is closer to 106, I see it making good torque down low and falling off around 5.5k. If it's closer to 110, I see it making good midrange between 4.5k-6k. The problem will be either nothing to carry it into the higher rpms, or a very narrow power band. You could go with a 1.6 rocker on the exhaust and -2* cam timing to try to push the power band higher.
try again
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Old Mar 9, 2011 | 08:58 AM
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LT1s don't typically have P2V issues.
I ran a 236/248 104LSA .610" cam in my 383 with -13cc pistons, a zero deck and .029" gaskets.
No issues at all with 2.055" and 1.600" valves.
Oh, and my heads were milled down to 56cc.
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Old Mar 9, 2011 | 10:50 AM
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Originally Posted by 93Z2871805
Well, depending on your heads, if your ICL is closer to 106, I see it making good torque down low and falling off around 5.5k. If it's closer to 110, I see it making good midrange between 4.5k-6k. The problem will be either nothing to carry it into the higher rpms, or a very narrow power band. You could go with a 1.6 rocker on the exhaust and -2* cam timing to try to push the power band higher.
Seriously?
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