I've just been drooling the entire build thread for this car.
Your craftsmanship is quite impressive and your swap is beyond unique.
I'm glad you went with the 4.8 (or the 5.3 you thought you bought.) The 4.8 is about as stout as the 5.3 and guys are running over 1000whp on stock internals. The nice part about the 4.8 is you can easily rev it higher than the 5.3L. Most of my close friends are LSx fiends, from 1000hp GTOs with a built 6.0L LQ9 converted to Automatic, to a 5.3L FC RX7 that runs low 9's spinning the tires to the 1000' mark, or a 4.8L Fox Body with a "large" turbo.
I'm definitely subscribing to this thread. I can't wait to see what you get done with the car. Best of luck!
Oh! And nice welds too.