Graham, the height of a 997 block is exact same as a 998/1098. You can fit a whole 1098 rotating assembly straight in (after boring) as my mate did back then, when his 997 crank busted.
It cost him `very little' as he was a BMC apprentice at Zetland.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Every job has its perks.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Hmmnn I've got an array of pistons sat at the back of my bench, and a couple of 997 blocks that have been decked like this, I was sure it was due to piston crown to pin height differences

I'll have a check tonight, may even put some pics up of 997 blocks and the differences! For the anoraks and hose clamp brigade!

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Sir Alec! we are not worthy!