INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

Cam Spec

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Old Mar 2, 2018 | 07:48 AM
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Default Cam Spec

Looking for a new cam for the 383 in my truck, my mods are:

5.7 bored (block out of my '02 Camaro)
4" Crank, 6.125 rods with pistons to match
PRC 1.5 heads, 61CC - 2.04 int - 1.575 exh, 650 springs
Vic Jr. 42lb inj, 90mm TB
Walbro 450 with Regulator and return
Monster Built Trans, 2800 Circle D verter
Yukon Posi, 3:73 gears
3" x 4" drop
Pantera Sticker in the back glass!!

My current cam is a 612/612 -242/244 @.050 (294/307 advertised) 113 lsa + 17 overlap.

Would like a bigger, more choppy cam that is still daily drive-able and reliable for the next 20 years. I know nothing about cam specs, had a friend spec this one.

What else do you need to make a cam recommendation? Thanks!!

Chad

Last edited by ss4chad; Mar 2, 2018 at 08:00 AM.
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Old Mar 2, 2018 | 09:48 AM
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More choppy and still drivable...

I think you will find more chop in your tune than you will with a new cam. Do you want to change the power characteristics of the cam you have? DO you know what tie intake centerline is?
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Old Mar 2, 2018 | 10:29 AM
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Thanks Vortec, the cam that is in it (or the spec of the cam) is notorious for drawing a large amount of vacuum, enough that it is sucking oil out of the motor and into the catch can. Almost a full can every 30 days.

They guy who spec'd it said he had 4 other guys come in with the same, or similar, setup that were also filling the catch can. So I have a chance to change it because I am pulling the motor and installing a different block so all of the parts in this motor will change over to a new motor.

This cam isn't as lumpy sounding as one I had in it with a stock bottom in. With the 383 I would like a cam that sounds as bad as the motor cubic inches indicates.

DISCLAIMER: Yes, this is trivial to have a "lumpy'er" sounding cam. I know, should be concerned with HP, I get that. But pulling into the gas station to fill up with a cam that sounds like its about to exit the motor is cool as hell. Nobody there will know how fast or how much horse it has, but they will hear it!!

Don't call me gay or say it's dumb to want the big loping cam sound. You have to admit that a big lope'n cam sounds badd ***!! Plus if I can push some RWHP thru it as well then WINNER WINNER CHICKEN DINNER!!

Chad
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Old Mar 2, 2018 | 11:17 AM
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That’s not a cam problem that’s a PCV Problem that needs addressed. You must have way too much air volume being moved by the pcv. Restrict it.
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Old Mar 2, 2018 | 12:54 PM
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Ok, I am running a line from the air intake tube (down stream of the air filter before the TB) to the clean side PCV flow (passenger side) for fresh air to the block.
Then I have a line from the driver side - (truck valve cover with built in fixed orifice restrictor) - that tee's in with the line coming from the LS6 Valley Cover that goes to the Catch Can and then from the catch can to the vacuum port on the intake downstream of the TB.

https://ls1tech.com/forums/generatio...fo-needed.html

Got this layout and recommendation from here, Post #10 is my setup.

I took the line off from the Catch Can to the downstream of the TB because there was oil starting to pool around the outside of the runners and making a mess. I installed a small K&N filter at that location.

Either way the can was getting filled very quickly. What are your thoughts? Still going to change the cam but would like to know why it is pushing or pulling oil out if it's not the fault of the cam.

Chad
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Old Mar 3, 2018 | 01:40 PM
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Default Pvc

that PVC setup is wrong
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Old Mar 3, 2018 | 08:28 PM
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Originally Posted by turboal1
that PVC setup is wrong
And the correct setup is.................?

Thanks for your input, but unless you have a solution that details the mechanics of the "correct setup" then please refrain from posting.

Chad
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Old Mar 3, 2018 | 08:32 PM
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Originally Posted by darkirish63
Yep...I run a Stroker in my rig as well. Passenger side vacuum draws from the intake tube and the PCV side has the fixed orifice valve going into a Mighty Mouse catch can to the LSXRT intake. Maybe a couple ounces every 3k oil change.
I get about 5 to 6 ounces evey month. Other than the LS6 Valley Cover, we have the same setup. Maybe I should block off one of them?

Chad
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Old Mar 3, 2018 | 08:33 PM
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Originally Posted by 03sierraslt
That’s not a cam problem that’s a PCV Problem that needs addressed. You must have way too much air volume being moved by the pcv. Restrict it.
Yep...I run a Stroker in my rig and I run the passenger side vacuum from the intake tube and the drivers side PCV through a fixed orifice valve to a Mighty Mouse catch can to the LSXRT intake and I don't get more than a couple ounces every 3k oil change. Pic attached.
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Old Mar 4, 2018 | 06:46 AM
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If you have a ls6 valley cover then make both valve covers your fresh air source, pull your crankcase vac from the valley cover. Hook up a vac gauge and use a restrictor to limit your idle vac to like 3-5”

For reference a stock cam pulls way more vac then your larger cam.

That cam should sound great if tuned right. What’s your hot idle rpm?
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