Man stock car brings back memories. It'll be a lot of fun.
Things I learned about my 98:
Computer is slow, but works.
98 rod bolts are weak; 7k rpm = spun bearing. Never, not even once, especially 7k under load.
LS6 intake will give you ~10hp
T-56 requires upgrades; 3-4 shift fork, paper to CF pads, keys etc, it's fairly well document. After this stuff, it's near bullet proof.
The 10 bolt WILL break; keep a fund for a replacement.
I still have some 98 Stage 2.5 5.3l heads on hand that need the valve guides replacing after going LS3.