Description:

GM 3988313 — Engine Bearing (Valve Train / Rocker‑Related Bearing)

Group 0.539 — “Valve Mechanism Bearings”

📘 Part Overview

• GM Part Number: 3988313

• Group Number: 0.539

• Nomenclature: Bearing, Valve Mechanism

• Function: Supports rocker arm or valve lever movement

• Era: Late 1960s–1970s GM service part

• Packaging: Small GM blue‑and‑white box 

🚗 Fitment (Catalog‑Based Engine Family Identification)

Because GM did not publish model‑specific lists for these micro‑bearings, fitment is tied to engine families, not vehicles.

Most common engine families using 0.539 bearings:

• Chevrolet Inline‑6: 194, 230, 250, 292

• Chevrolet Small‑Block V8: 283, 307, 327, 350 (select rocker support applications)

• Chevrolet Big‑Block V8: 396, 402, 427, 454 (limited)

• GM Industrial / Marine variants

These bearings typically support:

• Rocker arm pivots

• Rocker shaft supports

• Valve lever pivots

• Upper valvetrain motion points