Well... Hopefully my math is off. Based on the measurements and the formula I came across, with these pistons and an H89 head, the compression ratio works out to 8.08:1???!! That can't be right can it!?
Bore: 76.3mm
Stroke: 77mm
CChamber Volume: 30cc
Gasket Thickness: .8mm
Piston Dish: 2cc
Above Deck: 3mm
or Above Piston Volume: 15.717cc
I used a gasket Bore size of 79mm because that's all I could find but I assume there is a more appropriate size?
Any thoughts anyone?

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I got 8.12 but I allowed ever so slightly different figures for gasket bore and thickness. If you _hypothetically_ machined the block deck to get 0 deck height, that alone would bump it up to 10.9:1 . Taking 3mm off the block deck is a lot, I'd be reluctant to take that much off unless it was inspected and would safely take it. Then the issue might arise that if you went to the next piston oversize down the track that it might sit higher up and far enough above the deck to make it unworkable.

If that isn't a drama, then the 3mm or so off the block will also give you some quench area (making it less detonation prone) .

If you only took 1.5mm off the deck you'd have around 9.3:1 but the gap between the outer edge of the piston (the flat bit outside the dish) would be too far down from the head surface to give worthwhile quench, so it would be a little closer to detonation (relatively).

I suppose it'd really depend on teh cam choice too. If you stick with a very short/stock cam, then the comp ratio has to be a little lower. If you ran a bigger cam, more duration and overlap, you pretty much 'must' run more compression to get it to work well (esp the lower rpms below the cam sweet-spot)

Hey jmac,
Thanks for the feedback... I found the problem which was an A12 Crankshaft.

Awesome. Get the block decked to get the compression back. The A12 short stroke revs so hard, the A14 can't beat it.

I don't think I can take 3mm of the block can I? Plus I'd be giving up displacement which equals less power, yes?

You can take 3mm off the block. Yes, it'll be down in power from an A14, but it is said it will "rev harder".

Id try find an a14crank, with the right treatment it will rev plenty hard enough and drive harder of the mark!

From experience, if you skim the block more than 1.5 or 2mm you need to load the head studs or bolts a few times before you do your finnal pass in the mill, reason being that it will make a slight buldge around all the head stud holes (besides oil hole) due to the slight change in loading area, also a good idea to add a tiny champher as the threads start to stop the top thread pulling up slightly.

I have seen people taking 4mm off between head and block, one must just remember to take into account what it does to the rocker angle, for most that run cut cams its actualy good because it makes it easier to get the perfect rocker ratio.

If it is an A14 block, why not fit an A14 crank?

I would... I don't have one. I'm in the market.......