Yes the LS1 is a powerful and efficient engine indeed, but as was mentioned before, Is not an economical choice for swapping into a third gen.. Although anyone who accomplished it would definatly have my respects, I think an idea like that would be best left to a show car..
The reason I suggested a stroked 383 is because thats what I plan on doing with my Z when I get some cash together.. Then, You could do all the research and work, and let me know how it goes?
And he didnt say ANYTHING about efficiency!