Pontiac 346ci Specs: 3.898 x 3.622 in

Pontiac 346ci specs: 3.898 x 3.622 in (99 x 92 mm) bore and stroke. Displacement, compression and factory ratings for each, plus rod ratio and piston speed.

At a glance

Displacement	346 ci
Cylinders	8
Bore	3.898"
Stroke	3.622"
Compression	10.2:1
Advertised power	305–350 hp
Years	1998–2004

This engine

Engine	Displacement	Bore × Stroke	CR	HP
Pontiac 346ci · 3.898" × 3.622" · 10.2:1	346 ci	3.898" × 3.622"	10.2:1	305–350

Factory cars with a Pontiac 346ci

• Pontiac Firebird: 1998, LS1, 305 hp; 1998, 320 hp; 1999, LS1, 305 hp; 1999, 320 hp; 2000, LS1, 305 hp; 2000, 320 hp; 2001, LS1, 310 hp; 2001, 325 hp; 2002, LS1, 310 hp; 2002, 325 hp
• Pontiac GTO: 2004, LS1, 350 hp

What varies across the family

This family is represented by a single engine in the database: 346 ci, 8 cylinders, a 3.898" × 3.622" bore and stroke.

All are oversquare — bore larger than stroke, which favours revs over low-end torque.

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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