It's been a few years since all the work was done so I cant say exactly how much was removed. Lots of work was done to the inside of the block and to the crank to ensure everything would fit. Just be careful when fitting everything together and you shouldn't have any major problems.
See my photo's if you want to see which block was used. It's the block with the dizzy located at the front of the block.

Thanks for the tip. How much did you have to remove from the A14 crank counterweights to get it to fit?

2332owner,
I have a bored and stroked A12. My block is a 71 model and runs an A14 crank. Hope this helps.
Oh and by the way - you wont be able to run your new stroked motor whilst the oil dipstick is installed otherwise the crank will eat the dipstick. I just use a dummy dipstick and keep the original one in the cabin and use it when I have to check the oil.
There is not much room inside the little A12 block when you are swinging an A14 crank.

Paul.

I'm looking to make an A12 like Dodgeman's friend with the A14 crank. Question is, I've heard the newer A12 blocks (which are plentiful) can't be bored as far as the old, 71-73 blocks. Matsuoka has Wiseco make them 77mm A12 pistons and I'd like to go that route but I'm not sure which block to try it with. Thanks for any help in advance.