Will there be a possibility to recreate the Lamborghini Miura? Transverse v12.
Engine, gearbox, final drive housing in one casting.
The Cizeta? Transverse v16 with 4 cylinder heads.
And will it be possible to make the GMC v6 engines, 305cui - 478cui?
And the 702cui v12, uses the heads(4), pistons and conrods from the 351cui v6.
702 cui are “only” about 11.5L capacity, while the maximum capacity for V12s in Automation will be about 16L 
That also means that yes, you’ll be able to make 478cui V6 engines… as that is 7.8L and Automation will allow up to 8L capacity on those.
There will be no “special” configurations available though, as modeling them would take ages for very little in return.
What is the maximum cylinder diameter in a large engine?
Because the GMC 478 has a bore of 130.175mm and a stroke of 98.044mm (5.125"x3.86")
The limitations are 120 mm by 120 mm.
Ok. Bugger, it would have been fun to build that very odd engine.
Have to settle for the v12 only.
250hp @ 2400 rpm, 795nm @ 1600-1900 
You can search on YouTube for GMC Twin-six.
youtube.com/watch?v=qjw3W0Ml9yA