LS1 346 - Aluminum block, 241 heads
LS6 346 - Aluminum block, 243 heads and a little bigger cam, better intake
LS2 364 - Aluminum block, 243 heads 90mm intake and TB, drive by wire
LS3 - Aluminum block, 6 bolt heads, square port no more cathedral port
LS7 427 - absolute N/A monster. C6 Z06 motor 500Horse outta the box $13,499 from GMPP
LS9 - you can't afford it. 6.2L supercharged 638RWHP off the show room floor (ZR-1)
LQ4 364 - basically an iron block 6.0 with garbage heads, intake, and cam. If your replacing that anyway, this is for you
LQ9 364 - just like the LQ4 but with a little higher compression.
btw I have a ECU and harness that I was going to use for a project that I sold long ago if your interested. Found it cleaning the garage yesterday. $50 plus shipping.