Yup, tr220 112 lsa will give you a small lope. 114 lsa will be smoother. Keep in mind that you will need to change your valve springs and possibly push rods.
Also check out Texas speed's 220 cam
Definitely want hardened pushrods. Go with the complete cam kit from either Thunder or Texas speed. You are also going to need a front cover gasket, front crank seal, water pump gaskets, crank bolt and new fluids. If it were me I would go tr220 BC I like thunder. But the Texas speed 220 would work just fine. I would also put a ls6 oil pump, ls2 timing chain and ls7 lifters in there at the same time but its not absolutely necessary, just more of an insurance factor
04 RCSB 5.3, Homemade 80mm FM, TU1, TH400
Im sure you could reuse them all, but i know im not just because i dont want to have to redo somthing, you know. And you can even reuse gm mls head gaskets as well if you want. My roommate has pulled his heads 3 times and is still using the same gaskets lol. Its just a preference thing you know
04 RCSB 5.3, Homemade 80mm FM, TU1, TH400