Had a day filled with LSx stuff today, talking to 2 different guys who both have several LS vehicles, one with 4 swapped cars and a 70s f350 truck of his own.
The guy with the plastic block told me to check out this article which sold him on the LSx motors (1200hp on a stock 5.3 with ebay turbos) and the "sloppy mechanics" that have a lot of info about LS motors and do alot of obsurd things with them to make power and just to prove the reliablilty.
https://sites.google.com/site/sloppywiki/
http://www.hotrod.com/techarticles/hrdp_1109_stock_gm_ls_engine_big_bang_theory/
He had a notch fox body mustang with a 5.3/4l80 and a borg warner turbo, with the exception of a lunati cam, upgraded valvesprings and 6.0 heads i believe, everything else was stock and he's making 700hp on pump gas.
thought some of you might find those somewhat informative.