twin engined cars

here is a question i saw a z100 thingy on the net using 2 bike engines with a transfer box to put the power into one drive shaft to power the rear wheels, my question is: would that be possible to do that say with two 2ltr turbo engines run them into a transfer box and then to a gearbox to take the power, also the VW W12 engine two V6 cable tied together how do they do it? i'm out of my depth and can't find much info on anything to do with this. so can someone help explain thanks, would solve a lot of arguements with friends over the topic :P.

thanks very much

Well, the question I can answer is about the W12. It's not so much two V6's cable tied together, it's two VR6's sharing the same crank. (note: the VR6 is VW's Extremely narrow-angle V6. How narrow? One cylinder head for all 6 cylinders. Like...15 degrees if memory serves...)