Pontiac 347ci Specs: 3.938 x 3.563 in

Pontiac 347ci specs: 3.938 x 3.563 in (100 x 90.5 mm) bore and stroke. Displacement, compression and factory ratings, plus rod ratio.

At a glance

Displacement	347 ci
Cylinders	8
Bore	3.938"
Stroke	3.563"
Years	1957

This engine

Engine	Displacement	Bore × Stroke	CR	HP
Pontiac 347ci (1957)	347 ci	3.9375" × 3.5625"	—	—

Factory cars with a Pontiac 347ci

• Pontiac Bonneville: 1957

What varies across the family

This family is represented by a single engine in the database: 347 ci, 8 cylinders, a 3.9375" × 3.5625" 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.

← All Pontiac engines