With any turbo pump gas car you wanna stay away from high compression. While resurfacing the head will not add a substantial amount of compression, probably less than .1, it shouldn't be an issue. I would however advise you to maybe get a thicker one anyways just to help with longevity of the motor. I am not sure of your stock HG thickness so someone else will have to chime in on this and advise what the stock thickness is and we can go from there.

depends on how much the head has been surfaced.

new head thickness on a 4g63 is 5.200
mits says you can remove a combined total of .008 from the head/block
AREA says you can remove .015 from the head.

the head needs to be measured at 4 points, 2 down the intake side and 2 down the exhaust side

if your head thickness is between 5.200 and 5.185 a stock gasket will be fine.
if your 5.185 or thinnner get a head gasket that will restore heat thickness to between 5.200 and 5.185

the gasket you will use will be figured by adding OE headgasket thickness plus the amount to restore head thickness.

for appox every .007 milled from the head, you close the combustion chamber by 1cc

Also DO NOT let the machine shop "belt surface" your head!!
http://www.dsmtuners.com/forums/cyl...0613-why-not-let-your-head-belt-surfaced.html

depending if you choose to run a MLS or composite gasket, the gasket surface should look about like this.
http://www.dsmtuners.com/forums/new...face-4g63t-cylinder-head-mls-head-gasket.html

since the head is off you may want to do this oil mod too
http://www.dsmtuners.com/forums/newbie-forum/341028-4g63t-head-oil-port-mod.html

Are there such things as thicker composite H.G ?

Also the .045 min piston to valve clearance, is that based on a min head thickness of 5.185 ? so is it 5.185+.045=5.230 combined head and gasket thickness.

is the oem crushed thickness is .051 , what is the oem piston to valve clearance with a head at 5.200 ?

i ask since i don't want clearance problems and fly cuts and digging into the seats seems like more work. So far .071 is the thickest H.G i see sold MLS for the 4g, i know that drops comp, but im ok with it at 9.5:1 comp already as long as it provides max clearance, also would like not to have to deck block is possible thus my question about composite.

Like Dale said, 5.2" is stock when measured from the outcroppings. However, you only have one oil supply hole to the head and it shares space with a head stud/bolt. It's better to be on the fatter side of spec there. A thicker head gasket can help here, but you don't want to go overboard. This should answer all of your questions:

Milling the head will tighten up the quench; which is a good thing. Use the standard (or thinner) head gasket.

The oil port mod is advisable.

JacksonAuto said:

Milling the head will tighten up the quench; which is a good thing. Use the standard (or thinner) head gasket.

The oil port mod is advisable.

Click to expand...

Unless, your worried about clearance then the thinner H.G is something one would avoid.

It would take a hell of a lot of milling and big cams to create PtV issues.

Using a thicker HG to compenstate for milling will cause more harm than good.

JacksonAuto said:

It would take a hell of a lot of milling and big cams to create PtV issues.

Using a thicker HG to compenstate for milling will cause more harm than good.

Click to expand...

Which I suspect is my case.. Won't know until a few weeks.

question what will be harm it can cause?

A stock 1g runs 7.8 to 1 compression so I wouldn't even worry about not having enough compression. I would highly recommend a Mitsubishi MLS gasket. A little pricey, but would be cheaper in the long run if you have to replace a cheap one a year from now.
We all have to pay to play, I've learned do it right, do it once.

miliman13 said:

question what will be harm it can cause?

Click to expand...

Using a thicker head gasket increases the quench area. Makes for a less efficient chamber, less power and more likely to detonate.