M20 / M21 / M22 ● Confirmed

Pontiac · Regular Production Option

4-speed wide / close ratio / HD close ratio

Years 1970–74 Models 1

Documented applications

Firebird / Trans Am →

• 1970–1974 ● Confirmed

  M22 behind SD-455 & 455 HO

  Grade note: confirmed (M20/M21), single-source (M22)

This page aggregates every documented appearance of M20 / M21 / M22 in the Pontiac reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.