I'll be putting together a 1.9 block and a 2.0 head for my 3rd gen soon(hopefully soon), and I have 2 "simple" choices. Either I can use the stock HG or a copper one. I've read enough that I'm not worried about corrosion from the copper, so that needn't be mentioned. What I do care about is not losing too much compression when I change from the domed 2.0 pistons to the dished 1.9 ones. Hence the coper HG which comes in 0.020" thick easy and cheap from eBay or RockAuto. The stocker(measured quick and dirty with a digi mic) shows about 0.083" at the fire rings. I'm guessing(thoroughly) around 0.078"-0.080" after torquing the head down, so using the CU HG would give a NICE bump on the uber cheap, and I know they take abuse very well. I'll do actual measurements with clay when I start the build, but I'm just looking for opinions right now. I did search, but all I found was warnings not to use a CU HG(which I'll obviously ignore), and an OLD build that I didn't see a finish to where a CU gasket was mentioned. I believe the method will be: 1. Clay with stock old HG to find actual C/R and see if I want to bother. 2. Possibly decide to use the CU one instead and still clay it to find what I'll end up with, C/R wise. Again, apologies if this info is already somewhere. I looked and didn't see it. I appreciate any input.