LT3 Specs - LT3The Pontiac Sunbird GT and Pontiac Grand Am GT, came with a 2.0 litre, 8 valve, single overhead cam (SOHC), and a watercooled Turbocharger (Garrett T-25). The engine code is LT3 (C20GET). 2 Versions of this engine are produced still today as the C20XE and the C22XE, by Daewoo.
The engine is actually an Opel design but was assembled in Brazil. The bore and
stroke are the same (3.386" or 86 MM) which is what you call a "square" engine - the bore and stroke are equal. An "undersquare" engine has
a small bore and a long stroke for more low end torque but less high rpm power while an "oversquare" engine has a large bore and a short
stroke which allows it to make power at higher rpm but sacrifices low end torque. So I guess the "square" engines do a little of both!
Engine Code: LT3
Bore x Stroke: 3.386x3.386 (in)/86.0x86.0(mm)
Displacement: 121 cid, 2.0L
Firing Order: 1-3-4-2 (No.1 cylinder at timing belt end)
Compression ratio: 8.0:1
Intake valve size: 1.69"
Exhaust valve size: 1.44"
Camshaft duration: 214 degrees at .050"
Camshaft lobe centers: 114 degrees
165 hp @ 5600 rpm at 7 psi of boost
175 ft-lbs. of torque @ 4000 rpm