Stock exhaust manifolds vs headers

Rick posted while I was hunting and pecking, I agree with the compression increase. All pros and no cons unless you get crazy.
Between the block and head I used, I had 0.100" milled off in my rebuild and ended up with exactly the 8.4:1 that these engines were advertised as having been, in the first place.
Meaning that as built, stone stock, the fell way short of "advertised".
I was actually going for closer to 9:1 but having bought and started with a basket case of a pile of /6 parts that became my engine I had no baseline measurements for depth of piston top at tdc, etc to go off of, so the amount milled off of my head and block was a wild assed guess as to how much to mill off.