454 CID (7.4L) / 502 CID (8.2L)
SERVICE MANUAL NUMBER 23
Page 3A-15
90-861326--1 MARCH 1999
7.4L MPI (L-29) Engine Specifications (Continued)
VALVE SYSTEM
MODEL
7.4L
Lifter
Hydraulic Roller
Rocker Arm Ratio
1.70 to 1
Face Angle (Intake & Exhaust)
45
°
Seat Angle (Intake & Exhaust)
46
°
Seat Runout (Intake & Exhaust)
.002 (0.05) Max
Seat Width
Intake
.0300-.0600 (0.7620-1.5240)
Seat Width
Exhaust
.0600-.0950 (1.5240-2.4130)
Production
Intake
.0010-.0029 (0.0254-0.0737)
Stem
Production
Exhaust
.0012-.0031 (0.0300-0.0787)
Clearance
Service
Intake
.0037 (0.0939)
Service
Exhaust
.0049 (0.1244)
Valve Lash (Intake and Exhaust)
Net Lash
CYLINDER HEAD
MODEL
7.4L
Gasket Surface Flatness
.004 (0.1016) Overall Maximum .003
(0.076) within a 6 in. (152 mm) Span
MODEL
7.4L
Lobe Lift
±
020 (0 051)
Exhaust
.284 (7.214)
Lobe Lift
±
.020 (0.051)
Intake
.282 (7.163)
Duration at 050 In (1 27mm) Cam Lift
Exhaust
209
°
Duration at .050 In. (1.27mm) Cam Lift
Intake
209
°
Journal Diameter
1.9482-1.9492
(49.485-49.509)
Journal Out Of Round
.001 (0.025) Max
Camshaft Runout
.002 (0.051) Max
Timing Chain Deflection
.375 (9.5) from taut position
[Total .75 (19)]
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