Valve Spring Installed Height

Measure from spring seat (or top of shim) to top of valve shield. If specifications exceeded, (see Valve Springs Table for "Valve Closed" specification), install @ 1/16" spacer under spring to bring within limits.

CAUTION: Never shim spring to give installed height less than minimum specifications.

VALVE SPRINGS

Engine

Free Length

⁽¹⁾ PRESSURE (LBS.)

Valve Closed

Valve Open

1965

283", 327"

2.08"

78-86@1.66"

170-180@1.26"

1966

283"

1.94"

78-86@1.66"

170-180@1.26"

327"

1.94"

78-86@1.66"

170-180@1.26"

(350 HP)

1.94"

78-86@1.66"

180-185 @ 1.21"

1967-72

All

2.03"

76-84@1.70"

194-206@1.25"

1973

Int.

2.03"

76-84⁽⁾1.70"

194-206@1.25"

Exh.

1.91"

76-84@1.61"

183-195@1.20"

⁽¹⁾	Includes damper if used.

Fig 1: Valve Timing Marks

Courtesy of GENERAL MOTORS COMPANY

CAM LOBE LIFT

LIFT

Engine & Year

Intake

Exhaust

1965

283"

.2658"

327" (250, 300 HP)

.2658"

(350, 365, 375 HP)

⁽¹⁾

1966

283"

.2658"

327" (275, 300 HP)

.2658"

(350 HP)

.2981"

1967

283" & 350"

.2600"

.2733"

327" (210, 275, 300 HP)

.2600"

.2733"

(325, 350 HP)

.2981"

1968

302"

.3234"

307" & 350"

.2600"

.2733"

327" (210, 235, 250, 275, 300 HP)

.2600"

.2733"

(325, 350 HP)

.2981"

1969

302"

.3234"

307"

.2600"

.2733"

327" (210, 235, 250, 275, 300 HP)

.2600"

.2733"

(325, 350 HP)

.2981"

350" (255, 300 HP)

.2600"

.2733"

(350 HP)

.3000"

.3060"

(370 HP)

.3234"

1970-71

307"

.2600"

.2733"

350" All (Exc. 330 HP)

.2600"

.2733"

(330 HP)

.3057"

.3234"

400"

.2235"

.2411"

1972

⁽²⁾ 307"

.2600"

.2733"

⁽²⁾ 350" (165, 175 HP)

.2600"

.2733"

(255 HP)

.3057"

.3234"

⁽²⁾ 400"

.235"

.2411"

1973

307"

2600"

2733"

350" (145, 175, 190 HP)

2600"

2733"

(245, 250 HP)

3000"

3070"

400"

2235"

2411"

⁽¹⁾	Chevelle & Chevrolet.2981"; Corvette.3233".

⁽²⁾	California Camshafts, Intake.2671, Exhaust.2733"