c5blkvette

I have LS6 heads with 2.02/1.575 valves. How much can I mill them and still be safe for P/V clearance. I was thinking 0.020"

Also what is the compression ratio for 0.015", 0.020" and 0.030" shaved LS6 heads? I believe stock is 10.5:1

DenzSS

Do yourself a big favor and do not get your heads milled. Have the chambers welded instead.

c5blkvette

Why do you say this? Do you think there will be P/V issues even with 0.015" milled?

Any one else have any thoughts?

c5blkvette

ANYONE??????

I am taking them to the machine shop this afternoon....

DenzSS

Basically, it is just a sloppy way to go about it. The correct way is to change the size of the combustion chamber.

When you mill, you decrease the deck thickness of the head, decrease your P to V clearance, and change your valvetrain geometry. There are reasons to mill a cylinder head. Increasing compression ratio is not one of them unless you have no other choice. If I'm picturing the stock LS6 chamber correctly, you're going to increase the shrouding on the valves as well.

c5blkvette

I will take your advise. Thanks.

BTL FED

iTrader: (9)

Milling a head .15 or .30 really doesnt change the geometry that much, Welding a chamber really takes someone that know what they are doing, and if they heat the head too much or not enough it can cause problems with the strength of the metal. A general rule of milling a head and compression is every .10 you take off you add .3 of compression. And I dont hink milling a head is the Cheap way of doing things, people have been milling heads for YEARS and YEARS. After you get them milled though, I would clay the pistons and turn the motor over by hand to check the clearance.

robertbartsch

I have LS6 heads milled .055 (SDPC ported from 2002)

Piston valve clearence will depend on the cam. Mine is 220/220, 561/561, 112 - a good street cam.

I don't recommend milling the head or filling in the chambers with aluminum welds; why do you want to do this - higher compression? Trust me - your better to avoid this.

DenzSS

Can you explain this? You're making very little sense. Raising the compression ratio is perfectly acceptable as is having the chambers welded and recut.