I agree with AKMark - there is a wealth of information on this board with broader, deeper, and more accurate information than you will find on Wikipedia.

On your question about "new" 6.2 blocks - the last ones GM installed were in the '93 models, so it is getting pretty long in the tooth. Others would know much more than me, but there really wouldn't be much advantage to trying to build a "new" 6.2. You could do a NA 6.5 build if you don't want to mess with the turbo either due to added complexity or increased size. There are a couple NA blocks swapped into cars posted here on the conversion forum that you could take a look at.