Milling Heads

[WARLOCK]

How much does everyone usually mill on thier heads? I am leaning torwards a 243 head on a 5.3 but may go with the 862s. I want to have high compression. How much should I have them milled?

[Sizzle Chest]

Whats "high compression"? For each .006 you mill you'll reduce the chambers by 1cc as a rule of thumb. So it depends on who you believe on your other thread (me or Quick ) regarding CR on an LQ4 with 243 heads.

If you think you are at 10.4:1, then you would probably need to mill .024-.03 to get to 11:1. Just decide on what CR you want and tell your machine shop to mill to that. There is a limit of course based on deck thickness and ptv clearance depending on your cam duration.

[trx2stroke4life39]

I am in the same boat. I do know that the 243 don't have enough deck thickness to make a safe high compression in a 5.3. I have a set of 862 I am going to port then have them milled for my 4.8, but i am not sure how much to mill them just yet. I am still trying to find out the max before there is a problem between the heads and the intake manifold from when the heads move down and narrow the distance between them and not allow the intake manifold the sit correctly.

[molitor]

I am still trying to find out the max before there is a problem between the heads and the intake manifold from when the heads move down and narrow the distance between them and not allow the intake manifold the sit correctly.

just install a .060'' thick cellulose gasket instead of the factory plastic compression ones. you can mill them quite a bit then

[trx2stroke4life39]

just install a .060'' thick cellulose gasket instead of the factory plastic compression ones. you can mill them quite a bit then

Thanks, were can I get them from?

[WARLOCK]

Anyone have milled heads on their 5.3s?

[Frenchy]

I'm considering it

[04redwt]

I am running 243's milled 0.030 at 59cc's seem to doing fine but just got the truck running.

[WARLOCK]

What gaskets did you use?

[04redwt]

I just used stock head gaskets.