You can't take what you know about 4 stroke engines like from cars and directly apply it to 2 strokes because they don't work the same.
The biggest problem with air cooling an engine is to balance cooling across the entire cylinder and head without having hot spots. Liquid cooling solves that problem handily. Since you don't have to worry about hot spots you can be much more aggressive with your porting, so more larger transfer ports which more effectively deliver the fuel/air charge from the bottom end into the cylinders, you can also run larger exhaust ports because you can keep them from burning away like they would on an air cooled machine.
So while the bore and stroke is the same its not like your engine is the same engine with just a cooling jacket wrapped around it.
Don't let that talk you out of dual carbs, many manufacturers did dual carbs on air cooled machines.
Raising sleds from the dead in north central MA.
'70 Ski-Doo Olympique 12/3 - The Yellow Bullet
'71 Arctic Cat Panther 303 - Wankle Panther
'78 Arctic Cat Pantera 5000 - Back from the dead!
'79 Polaris Cobra 340 - Back from the dead!
'95 Ski-Doo Grand Touring SE 670