Engine Tune-Up Specs 1970-72
* All timing figures are before Top Dead Center.
* Values in parenthesis are for California engines.
* Where two idle values are separated by a slash, the second is with idle speed solenoid disconnected.
ENGINE DIST TIMING-DEG INTAKE FUEL IDLE RPM TARGET
TYPE HP / PLUG POINTS W/TRANS VALVE PUMP-PSI W/TRANS COMP
CYL-DISP CARB TORQUE TYPE GAP DWELL GAP MAN AUTO OPENS PRESSURE MAN AUTO RATIO
__________ ____ _______ __________ __________ _________ _____ ________ ________________ _______
(1970)
6-250 Chevy 1v 155/240 R46T .035 31-34 .019 TDC 4B 16deg 4-5 830-750 630-600 8.5:1
8-350 2v 250/355 R46S .030 28-32 .016 10B 10B 16deg 5.5-6.5 750 575 9:1
8-350 4v 310/390 R45S .030 28-32 .016 10B 10B 16deg 5.5-6.5 650 575 10.25:1
8-350 (W31) 4v 325/360 R43S .030 28-32 .014 14B 14B 40deg 5.5-6.5 750 625 10.5:1
8-455 2v 320/500 R45S .030 28-32 .016 --- 8B 20deg 5.5-6.5 --- 575 10.25:1
8-455 Cutlas 4v 365/500 R44S .030 28-32 .016 --- 12.5 20deg 5.5-6.5 --- 600 10.5:1
8-455 Vista 4v 365/500 R45S .030 28-32 .016 --- 8B 24deg 5.5-6.5 --- 575 10.5:1
8-455 442 4v 365/500 R44S .030 28-32 .016 12B 12B 24deg 5.5-6.5 700 650 10.5:1
8-455 (W30) 4v 370/500 R44S .030 28-32 .016 8B 8B 56deg 5.5-6.5 700 650 10.5:1
(1971)
6-250 Chevy 1v 145/230 R46TS .035 31-34 .019 4B 4B 16deg 4-5 600 575 8:1
8-350 2v 240/350 R46S .040 28-32 .016 10B 10B 14deg 5.5-6.5 750 600 8.5:1
8-350 4v 260/360 R45S .040 28-32 .016 10B 12B 14deg 5.5-6.5 750 600 8.5:1
8-455 2v 280/445 R46S .040 28-32 .016 --- 8B 20deg 5.5-6.5 --- 600 8.5:1
8-455 4v 320/460 R46S .040 28-32 .016 --- 8B 20deg 5.5-6.5 --- 600 8.5:1
8-455 4v 340/460 R45S .040 28-32 .016 10B 10B 24deg 5.5-6.5 750 600 8.5:1
8-455 (W30) 4v 350/460 R45S .040 28-32 .06 12B 10B 56deg 5.5-6.5 765 600 8.5:1
(1972)
8-350 2v 160/275 R46S .040 28-32 .016 8B 8B(6B) 16(22) 5.5-6.5 750 650/550 8.5:1
8-350 Duals 2v 175/295 R46S .040 28-32 .016 8B 8B(6B) 16(22) 5.5-6.5 750 650/550 8.5:1
8-350 4v 180/275 R46S .040 28-32 .016 8B 12B 16(22) 5.5-6.5 750 600 8.5:1
8-350 Duals 4v 180/275 R46S .040 28-32 .016 8B 12B 16(22) 5.5-6.5 750 600 8.5:1
8-455 4v 225/360 R46S .040 28-32 .016 10B 8B 30deg 5.5-6.5 750 600 8.5:1
8-455 Duals 4v 250/370 R46S .040 28-32 .016 10B 8B 30deg 5.5-6.5 750 600 8.5:1
8-455 4v 270/370 R46S .040 28-32 .016 10B 8B 30deg 5.5-6.5 750 600 8.5:1
8-455 (W30) 4v 300/410 R45S .040 28-32 .016 12B 10B 56deg 5.5-6.5 750 650 8.5:1