Despite looking much the same, the Gen V LT block is a significant departure from the Gen IV LS block. There are a few architectural commonalities such as 9.24" deck height, 4.4" bore spacing, 6-bolt mains, starter provision, lifter geometry, transmission dowels, and 5 out of 6 bellhousing bolts. Nearly everything else has been revised including motor mount bolt pattern, knock sensor locations, VVT and DOD details, high pressure fuel pump provisions, head bolt sizes, and all new dowel-located oil pans and front & rear covers. All 5.3L (3.780" bore) and 6.2L (4.065" bore) blocks are aluminum and the 6.6L L8T block is iron with 4.065" bore. GM ended up with 4 variants of Gen V LT blocks:

1) Early Gen V, 2014-2019 L83, L86, LT1, LT4, LT5 aluminum blocks that include 8 AFM towers in the valley similar to Gen IV LS, driver side provision for block-mounted vacuum pump, piston oil squirters on all RPO.

2) Late "Gen V Plus", 2019-current L82, L84, L87 aluminum blocks with 16 DFM solenoids for all 8 cylinders in the valley, deletion of the vacuum pump provision, addition of oil pump locator dowels, piston skirt oilers deleted in 5.3L, revised high pressure fuel pump lifter hold down.

3) 2020-current L8T 6.6L iron block that includes AFM towers in the valley (but are not drilled since no DOD strategy for this RPO), knock sensor relocation, one front accessory hole and one passenger side skirt accessory hole relocated, includes oil pump locator dowels like Gen V Plus.

4) 2020-current LT2 6.2L aluminum block with significant revisions in motor mount pattern (now 3-bolt), starter provision raised and 2-bolt pattern revised, coil mounting provisions added to side of block, front cover pattern changed for dry sump and lifter valley scavenge pump, only 8 DFM solenoids in valley.

Video Discussion

For a full walk around and detailed discussion for all four LT engine blocks, see 0:24 to 10:22 of the full LT Swap Masterclass video on YouTube: