Ignition Timing

Set timing at idle speed with distributor vacuum line disconnected and plugged.

Engine

Synchro-mesh

Auto. Trans.

302"

4° BTDC

307"

2° BTDC

327" 210 HP

2° ATDC

2° BTDC

250 HP

4° BTDC

275 HP

TDC

4° BTDC

300 HP

4° BTDC

325 HP ⁽¹⁾

4° BTDC.

⁽²⁾

8° BTDC

350 HP ⁽³⁾

4° BTDC

350"

TDC

4° BTDC

396" 325 HP

4° BTDC

350 HP

TDC

4° BTDC

375 HP

4° BTDC

427" 385, 390, 400 HP

4° BTDC

425 HP

4° BTDC

430 HP

12° BTDC

435 HP

4° BTDC

⁽¹⁾	Distributor No. 1111444.

⁽²⁾	Distributor No. 1111478.

⁽³⁾	Except Distributor No.'s 1111475, 477 which are set at 8° BTDC.

Fig 1: Ignition Timing Marks (All Engines)

Courtesy of GENERAL MOTORS COMPANY