GMC 325ci Specs: 3.78 x 3.622 in

GMC 325ci specs: 3.78 x 3.622 in (96 x 92 mm) bore and stroke, shared by all 8 versions. Displacement, compression and factory ratings, plus rod ratio.

At a glance

Displacement	325 ci
Cylinders	8
Bore	3.780–3.780"
Stroke	3.622"
Advertised power	270–355 hp
Years	1999–2026

Engines in this family

Engine	Displacement	Bore × Stroke	CR	HP
LM7	325 ci	3.7799" × 3.622"	—	270–295
L33	325 ci	3.7799" × 3.622"	—	310
LY5 / LH6 / LMG / LC9	325 ci	3.7799" × 3.622"	—	315
LMG / LC9	325 ci	3.7799" × 3.622"	—	315
L83	325 ci	3.7795" × 3.622"	—	355
L8B	325 ci	3.7799" × 3.622"	—	355
L82	325 ci	3.7799" × 3.622"	—	355
L84	325 ci	3.7795" × 3.622"	—	355

Factory cars with a GMC 325ci

• GMC Sierra 1500: 1999, LM7, 270 hp; 2000, LM7, 285 hp; 2001, LM7, 285 hp; 2002, LM7, 285 hp; 2003, LM7, 285 hp; 2004, LM7, 295 hp; 2005, LM7, 295 hp; 2005, L33, 310 hp; 2006, LM7, 295 hp; 2006, L33, 310 hp; 2007, LM7, 295 hp; 2007, L33, 310 hp; 2007, LY5 / LH6 / LMG / LC9, 315 hp; 2008, LY5 / LH6 / LMG / LC9, 315 hp; 2009, LY5 / LH6 / LMG / LC9, 315 hp; 2010, LMG / LC9, 315 hp; 2011, LMG / LC9, 315 hp; 2012, LMG / LC9, 315 hp; 2013, LMG / LC9, 315 hp; 2014, L83, 355 hp; 2015, L83, 355 hp; 2016, L83, 355 hp; 2017, L83, 355 hp; 2017, L8B, 355 hp; 2018, L83, 355 hp; 2018, L8B, 355 hp; 2019, L82, 355 hp; 2019, L84, 355 hp; 2020, L82, 355 hp; 2020, L84, 355 hp; 2021, L82, 355 hp; 2021, L84, 355 hp; 2022, L84, 355 hp; 2023, L84, 355 hp; 2024, L84, 355 hp; 2025, L84, 355 hp; 2026, L84, 355 hp

What varies across the family

Stroke is constant at 3.622" across the family — the displacement spread comes from bore, so these share a crank and differ in the block.

Each engine page carries rod ratio, mean piston speed, bore/stroke character and cylinder head specs where published, and links into the calculators with its dimensions already filled in.

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