You can swap just about anything between any of the GEN III family of motors (4.8, 5.3, 5.7, 6.0). Heads, cam, intake manifold, exhaust manifolds, etc will all physically bolt to any of those blocks, but there could be interference/clearance issues based on what application you're working with.

For instance, you can't run F-car manifolds/headers on the NBS trucks because the simply don't route correctly to clear the frame. The intake manifold is the same--the LS1/6 intake will physically bolt to the iron blocked motors, but you have to make some modifications to the accessory brackets to get everything to work properly.

I swapped to an aluminum 5.7 LS1, and used all of my truck "peripherals" (intake/exhaust/accys). Everything lined up perfectly except for one bolt hole on the A/C bracket not having a corresponding boss on the block. Since there are 4 other bolts, I'm not too worried about it.

Good luck!