Early in the history of Duramax engines, GM changed the LB7 series of engines to LLY, but it can be difficult to tell them apart. Here’s how.

Early in the history of Duramax engines, GM changed the LB7 series of engines to LLY, but it can be difficult to tell them apart. Here's how.

The L96 crate engine kit includes the engine assembly with a production intake manifold, ... with engine codes LB7, LLY, LBZ and LMM. Both engines are on display at the 2017 SEMA show, ...