bones5133

iTrader: (1)

Hey guys,

I dropped my heads off at a local machine shop. I have a 2003 6.0L and I want to get the heads shaved .030 to increase the compression to that closer to 10:1 other changes: Tick Performance CAM springs, LS6 Intake, Trunion kit.

They had know idea what I was talking about.

They called me today and said my heads were factory thickness meaning they have never been milled before but GM specs or minimum thickness is only .023 to take off. And not a performance engine spec.

I am guessing this is just GM recommendations. All the articles I have found and read say to take .030

Can anyone advise and let me know what taking the .030 will bring my compression too?

Thanks

JakeFusion

iTrader: (7)

Milling .030" will take 5cc off the heads which will punch your compression up nearly .6 points... so 9.5:1 to 10.1:1. If you use a Cometic .040" gasket, you'll get up to 10.4:1. The added benefit of the thinner gasket is better quench for a more optimum burn and better spark/ignition timing.

However, if you do that, you'll need to check piston-to-valve clearance as you will be running .041" closer.

bones5133

iTrader: (1)

So .030 and factory gasket will get me a safe 10.1:1

If I use the .040 cometic gasket and don't have piston and valve clearance just go back to the factory gasket?

Mike_hawk

I have an 05 6.0 with 317 heads milled .040", I'm running a 224 comp cam and stock gaskets. The compression calculator put me at 10.2 to 1. If I were you I would also replace your lifters, better to do it now than to have to buy gaskets and bolts again.