A few thoughts on these engines. First, most parts interchange between the LS1 and LS6 Corvette engines. A fly-by-wire pedal was mentioned further up, but it isn't required. A throttle body from and 'older' engine and it's a typical cable throttle. When using a 5.3L, a cam and intake change from a LS6 will put you around 400HP. Gen III and Gen IV engines (4.8L, 5.3L, 5.7L and 6.0L) and reasonably simple to work with. There are a few HP books dedicated to these engines, and specifically show what is a straight swap and things to watch out for (lining up the oil pan with the front and rear covers).
Have fun with the swap!
