Pontiac 403ci Specs: 4.351 x 3.385 in

Pontiac 403ci specs: 4.351 x 3.385 in (110.5 x 86 mm) bore and stroke. Displacement, compression and factory ratings, plus rod ratio.

At a glance

Displacement	403 ci
Cylinders	8
Bore	4.351"
Stroke	3.385"
Compression	8.0:1
Years	1977

This engine

Engine	Displacement	Bore × Stroke	CR	HP
L80	403 ci	4.351" × 3.385"	8:1	—

Factory cars with a Pontiac 403ci

• Pontiac Catalina: 1977, L80

What varies across the family

This family is represented by a single engine in the database: 403 ci, 8 cylinders, a 4.351" × 3.385" 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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