Now that I'm putting the A12 back in the car it bumps me down in class and back into the small bore group (I was in with the 2.0 liter cars). I can run up to 1300cc

I also have an A12A bottom end that could be over bored. So are there any off the shelf pistons with 75-77mm and 32.5 pin height that are flat tops?

Holden gemini g16 77mm are flat tops and about 27.5 comp height from memory
strong units and often boosted as well but lighter than A14 units.

PJZ had some pistons but not sure if they were that big.

A12A has same pin height and pin diameter as A14, so A14+1 pistons can be used

off-the-shelf Kameiri forged from USA distributor or eBay $1600 includes shipping

Custom Wiseco forged $850. Complete set with pistons, pins, rings and clips. takes 6-7 weeks to get

A12A has same pin height and pin diameter as A14, so A14+1 pistons can be used

off-the-shelf Kameiri forged from USA distributor or eBay $1600 includes shipping

Custom Wiseco forged $850. Complete set with pistons, pins, rings and clips. takes 6-7 weeks to get

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  Kameari A12A-A13-A14 77mm.jpg (25.87 KB)

As I'm planning on making some kind of motor swap in the next 24 months I'm not looking to order another set of forged pistons.

Rockauto has 76.75mm pistons but obviously those are lower compression; even with a .6 head gasket the compression will only be 9.5-1 so I was hoping to get the comp up to 10-1 without resorting to ordering custom pistons.

found them! 77mm 4xc1 engine
Chev Spectrum on your end of the pond
https://www.ebay.com/itm/CHEVY-ISUZU-1 ... 9f3be6:g:uVYAAOxymcdRhAEx

https://www.precisionintl.com/Engine.aspx?ID=649

height 28.5mm dome (-0.9mm) therefore machining
the little dome should get you 27.4mm?

STD 020 040 (set of 4) Rings not included
Use PR1769 piston rings Compression height 28.5mm +0.5mm dome

http://www.totopiston.co.jp/cat/piston/toto11is-1.pdf

Wrong pin height. A12A/A12/A13/A14 pin (compression) height is 32.5 mm

That leaves only one choice: off-the-shelf 77mm Kameiri pistons available now

This seems a lot of effort sourcing a piston . Either deck the block or shave the head. I would go the block as they are easier to source / cheaper to buy, than a head now adays. Peter Zekert may have a set of used forged if you are definite on the piston option

No effort needed -- just buy the off-the-shelf pistons

Peter Z has no flat-tops, at least none right now listed on his web page. In the past he usually had domed pistons but is now recommending Wiseco customs

Note that flat-tops make more power than stock dish-tops do, even when the compression is raised by decking the head. Decking the block works well if the pin-height is too low. Block decking also works to improve quench area -- but then so does a thinner (competition) head gasket

4.5mm is not much off the top of the block
especially if you use studs with locktite

18mm pins is spot on for old rods