GM Service Manual Online
For 1990-2009 cars only

Engine Mechanical Specifications Unit Repair

Application

Metric

English

General Data

  • Engine Type

V-8

  • Displacement

7.4L

454 CID

  • RPO (VIN Code)

L29 (J)

  • Bore

107.95 mm

4.25 in

  • Stroke

101.6 mm

4.00 in

  • Compression Ratio

9.0:1

  • Firing Order

1-8-4-3-6-5-7-2

  • Spark Plug Gap

0.8890 mm

0.035 in

  • Oil Pressure (Minimum)

68.65 kPa @ 600 RPM

172.37 kPa @ 2000 RPM

10 psi @ 600 RPM

25 psi @ 2000 RPM

  • Oil Filter Torque

16 N·m

12 lb ft

  • Oil Filter System

Full Flow

  • Oil Pump Type

Gear Driven

Cylinder Bore

  • Diameter

107.950-107.968 mm

4.2500-4.2507 in

  • Out Of Round Production

0.0254 mm

(Maximum)

0.001 in

(Maximum)

  • Out Of Round Service

0.051 mm

(Maximum)

0.002 in

(Maximum)

  • Taper Production Thrust Side

0.0127 mm

(Maximum)

0.0005 in

(Maximum)

  • Taper Production Relief Side

0.0254 mm

(Maximum)

0.001 in

(Maximum)

  • Taper Service

0.0254 mm

(Maximum)

0.001 in

(Maximum)

Piston

  • Clearance Production

0.0457-0.0762 mm

0.0018-0.0030 in

  • Clearance Service Limit

0.0457-0.219 mm

0.0018-0.0048 in

Piston Ring Compression

  • Top Groove Production Clearance

0.031-0.074 mm

0.0012-0.0029 in

  • Second Groove Production Clearance

0.031-0.074 mm

0.0012-0.0029 in

  • Service Limit Groove Clearance

0.0991-0.305 mm

0.0012-0.0039 in

  • Top Production Gap

0.254-0.457 mm

0.010-0.018 in

  • Top Service Limit Gap

0.254-0.711 mm

0.010-0.028 in

  • Second Production Gap

0.406-0.609 mm

0.016-0.024 in

  • Second Service Limit Gap

0.406-0.863 mm

0.016-0.034 in

Piston Ring Oil

  • Production Groove Clearance

0.127-0.165 mm

0.0050-0.0065 in

  • Service Limit Groove Clearance

0.127-0.191 mm

0.0050-0.0075 in

  • Production Gap

0.254-0.762 mm

0.010-0.030 in

  • Service Limit Gap

0.254-1.016 mm

0.010-0.040 in

Piston Pin

  • Diameter

25.132-25.137 mm

0.9895-0.9897 in

  • Clearance in Piston Production

0.005-0.017 mm

0.0002-0.0007 in

  • Clearance in Piston Service Limit

0.005-0.025 mm

0.0002-0.0010 in

  • Fit in Rod

0.078-0.053 mm

Interference

0.0031-0.0021 in

Interference

Crankshaft

  • Crankshaft Run Out

0.051 mm

(Maximum)

0.002 in

(Maximum)

  • Main Journal Diameter #1, #2, #3, #4, #5

69.804-69.822 mm

2.7482-2.7489 in

  • Main Journal Taper Production

0.010 mm

(Maximum)

0.0004 in

(Maximum)

  • Main Journal Taper Service Limit

0.025 mm

(Maximum)

0.0010 in

(Maximum)

  • Main Journal Out Of Round Production

0.010 mm

(Maximum)

0.0004 in

(Maximum)

  • Main Journal Out Of Round Service Limit

0.025 mm

(Maximum)

0.0010 in

(Maximum)

  • Main Bearing Clearance #1 Production

0.043-0.076 mm

0.0017-0.0030 in

  • Main Bearing Clearance #2, #3, #4 Production

0.028-0.061 mm

0.0011-0.0024 in

  • Main Bearing Clearance #5 Production

0.063-0.096 mm

0.0025-0.0038 in

  • Main Bearing Clearance #1, #2, #3, #4 Service Limit

0.025-0.076 mm

0.0010-0.0030 in

  • Main Bearing Clearance #5 Service Limit

0.063-0.101 mm

0.0025-0.0040 in

  • Crankshaft End Play

0.127-0.279 mm

0.005-0.011 in

  • Crankpin Diameter

55.854-55.869 mm

2.1990-2.1996 in

  • Crankpin Taper Production

0.0127 mm

0.0005

  • Crankpin Taper Service Limit

0.025 mm

0.0010 in

  • Crankpin Out Of Round Production

0.013 mm

0.0005

  • Crankpin Out Of Round Service Limit

0.025 mm

0.0010 in

  • Rod Bearing Clearance Production

0.028-0.074 mm

0.0011-0.0029 in

  • Rod Bearing Clearance Service Limit

0.028-0.099 mm

0.0011-0.0039 in

  • Rod Side Clearance

0.033-0.584 mm

0.0013-0.0230 in

Camshaft

  • Camshaft Run Out

0.051 mm

(Maximum)

0.002 in

(Maximum)

  • Lobe Lift Intake ± 0.05 mm (0.002 in)

7.165 mm

0.2821 in

  • Lobe Lift Exhaust ± 0.05 mm (0.002 in)

7.221 mm

0.2843 in

  • Journal Diameter

49.471-49.522 mm

1.9477-1.9497 in

Valve System

  • Lifter

Hydraulic, Roller Followers

  • Rocker Arm Ratio

1.70:1

  • Valve Lash Intake

Net Lash

  • Valve Lash Exhaust

Net Lash

  • Face Angle (Intake & Exhaust)

45 degrees

  • Seat Angle (Intake & Exhaust)

46 degrees

  • Seat Runout (Intake & Exhaust)

0.051 mm

(Maximum)

0.002 in

(Maximum)

  • Seat Width Intake

0.762-1.524 mm

0.030-0.060 in

  • Seat Width Exhaust

1.524-2.413 mm

0.060-0.095 in

  • Stem Clearance Production Intake

0.025-0.0737 mm

0.0010-0.0029 in

  • Stem Clearance Production Exhaust

0.030-0.077 mm

0.0012-0.0031 in

  • Stem Clearance Service Intake

0.025-0.094 mm

0.0010-0.0037 in

  • Stem Clearance Service Exhaust

0.030-0.124 mm

0.0012-0.0049 in

  • Valve Spring Pressure Closed

316-351 N @ 46.685 mm

71-79 lb @ 1.838 in

  • Valve Spring Pressure Open

1059-1165 N @ 34.213 mm

238-262 lb @ 1.347 in

  • Valve Spring Installed Height ± 0.794 mm (0.0312 in)

46.685 mm

1.838 in