GM Service Manual Online
For 1990-2009 cars only

Select the proper size piston for each cylinder bore after cylinder has been honed.

Measure the cylinder bore. Refer to the table below for the correct size piston to use for that cylinder.

Piston ID

Cylinder Borer

Piston Size

mm

Inches

mm

Inches

(8)

85.975-85.985

3.3848-3.3852

85.940-85.950

3.3834-3.3838

(99)

85.985-85.995

3.3852-3.3856

85.950-85.960

3.3838-3.3842

(00)

85.995-86.005

3.3856-3.3860

85.960-85.970

3.3842-3.3846

(01)

86.005-86.015

3.3860-3.3864

85.970-85.980

3.3846-3.3850

(02)

86.015-86.025

3.3864-3.3868

85.980-85.990

3.3850-3.3854

7 + 0.5 Cylinder must be bored oversized

86.465-86.475

3.4041-3.4045

86.430-86.440

3.4027-3.4031