As I recall both 1mm dish and 2mm dish are common in USA for A14. Perhaps one was used in the FU Engine and the other is the 'regular' piston. There are at least three different combustion chamber designs in USA (two are unique to USA, the FU Head and the 1981/1982 head)

Sorry DD,
It was a separate question. I know I'll need to measure the dish plus the combustion chamber. I'm building a new A14 and I'm aiming for 10:1 compression. Wondering if I can get there with these pistons as opposed to having forged ones made.Although, I was also hoping to go for a 78mm bore...

this article says that for 1978, A14 dish was either 4mm or 5mm.

I haven't measured them yet, but just eyeballing this dish seems to be only 1mm deep, possibly 2 at the most....

I rebuilt an A14 engine for a workmate back in the 1980's & I bought two new [genuine] pistons to replace a couple of damaged items.

The new pistons had a much smaller dish than the originals & it became necessary to buy two more to match. I have no idea of the origin of the A14 & no idea what model that the new pistons were intended for but clearly there are a number of different piston & cylinder head combinations.

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?

Let's take Dodgeman's formula.

R squared x Pi x L [x number of cylinders if you want whole of engine displacement] divided by 1000.

76.3 ^2 * 3.1415 * 77 / 1000 = 1408 cc

Now take the combustion chamber:

29cc cylinder head chamber + 3cc Nismo 0.8 gasket + 4cc dish = 36cc

1408/4 / 36 = 9.78, but that's without considering deck height. 3mm seems a little too much deck height?

I just checked the stroke... Only 70mm. It's an A12 Crankshaft In the A14 block... There's my missing compression.

If that's the case then your compression ratio is even less than you thought because the swept volume of the cylinder[s] is less than you calculated, .. by approximately 8%

After cleaning the top of the pistons I found the number:9038P Does that ring any bells with anyone?