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L92 milling question

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Old Nov 11, 2008 | 08:37 AM
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Default L92 milling question

Guys, I am running a 6.0 LS2 and I have installed a Vengeance cam 224/235/610/620/115 and it runs awesome.

Here is my question.

I will be picking up a set of TSP CNC'd L92 heads (stock size valves) and I am having them milled .020 and need to know if the current 7.4 push rod will work? Anyone have any ideas?

In other words, if you mill only .020 off a head, will you be required to get a different set of push rods? I have been into Cobras for so long, I can't remember!

Stock LS2 pistons

Going to run Cometic's btw, if possible.

Last edited by JayplaySS; Nov 11, 2008 at 08:50 AM.
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Old Nov 11, 2008 | 08:55 AM
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what size head gasket?
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Old Nov 11, 2008 | 09:13 AM
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First, do you have valve reliefs for this combo? I'm afraid that exhaust lobe might cause some issue between pistons and valves. What lifters will you be running? With a .053" GM MLS gasket, you're should be in the area of 7.35-7.375" pushrods with the heads milled .020"! 7.375" will likely set you up close to .080-.100" preload.
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Old Nov 11, 2008 | 09:24 AM
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Originally Posted by Matt@Texas-Speed
First, do you have valve reliefs for this combo? I'm afraid that exhaust lobe might cause some issue between pistons and valves. What lifters will you be running? With a .053" GM MLS gasket, you're should be in the area of 7.35-7.375" pushrods with the heads milled .020" 7.375" will likely set you up close to .080-.100" preload.
Thanks Matt. They are the stock LS2 pistons and lifters. I guess I will have to go with the GM gaskets and 7.35 rod....????

I will verify that with Ron from Vengeance as well.

How did Jason have the heads set up when he ran them on his A6 I wonder. Stock compression maybe or a smaller cam.
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Old Nov 11, 2008 | 09:28 AM
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Jason's old car just has a 228R camshaft IIRC....GM MLS gasket, stock valves (they have better clearance than stainless), and only enough milling to ensure the heads were flat. The largest I've seen clear this combo recently was a GTO guy (ShoddyDog if you browse the GTO forums)...I cannot remember his PtoV clearance off hand though. He ran a 228/232.
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Old Nov 11, 2008 | 09:34 AM
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What is the difference in cc between LS2 heads and L92's? 69 vs 65?
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Old Nov 11, 2008 | 09:41 AM
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That is correct!
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Old Nov 11, 2008 | 10:25 AM
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Jason said he got 460rwhp with the L92 heads and the 228r cam so I guess I can run the 10.5:1 and be fine for now. He said that car was fun.

So that milling only a .010 clean up, GM MLS gaskets and 7.4 push rods? Correct?

Matt, I really appreciate the help.
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Old Nov 17, 2008 | 11:55 PM
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Just commenting here but I have an LS2 with L92 heads. My pistons have no reliefs in them. My heads were milled .040. I run a stock ls2 head gasket and my cam is comp xer lobes 232/242 .595/.610 113lsa. I dont have any PTV issues. My pushrods are 7.350. Hope I could help.
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