Aussie Speed head gasket.

yup. I measured several of them (fire ring diameter) with a dial caliper. I had a thread/question about this very thing, think it was on the /6.org site. 0.100ish shave to get down to 44 cc? what did yours start out at? 0.100" seems steep/ though I am disappointed that even after a 30-thou deck shave, my pistons are still 0.180" in the hole on my block. My block cleaned up at 20-over, so that was all I wanted it bored. I put stock type Silvolite pistons into mine.

being 0.060 thick vs 0.040ish like most other readily available gaskets, I know that more can be taken off the head when using the Aussie HG/ but for what I have for the rest of measurements so far, I'm looking at a target of around 48cc maybe 46 at the smallest.
I don't have a current CC of my head (waiting on mach. shop to call me with that info) but I'm hoping the "oops" on my head will shrink when milled, meaning that those CC numbers I'm hoping to get to would lock me into an Aussie, even if the outer dia of my chambers shrinks enough to use a regular HG.... if I ever have to pull that head again, once I get it back and assembled.... but I have asked what CC to expect my stock uncut head to measure out at, getting guesses at 54-56 cc so far and at 0.0066 shaved per cc removed, I was looking at a shave of "only" about 60-thou to get there and have the CR I want using the Aussie... Im going for just over, "as advertised in every manual known to Man that covers the /6" (which claims 8.4) I want about 8.7-8.8, definitely not over 9/ since I am building what I hope will be a 3 season driver, and I ain't forking over $.50-$1.00 PER GALLON for premium on every fillup, sorry, aint happenin.
and using the online calc link that 68Barracuda gave me on the other site, at 46-48 cc that will put me right in the CR range I think I want.
I got an Aussie HG I "borrowed" (I have to buy him one to replace it) from Slantzilla whom I don't believe is on this site but is on the .org site regularly and lives near me. I have like a dozen other /6 HGs here including 8, pre printoseal, gray asbestos looking Fel Pros, and 1 each of a few other different brands for a slant, Id love to be able to use what I already have here, as the Aussie ones aren't cheap. I'll probbaly be going to that guy on Ebay and buying his 3 pack (per-gasket, much cheaper than buying only 1 from him)..... 1 for "pay back" and 2 for ready spares in case I ever have to pull the head back off......