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Home >> Chevrolet >> 1981 >> Forward Control 7.4L Eng VIN W, Standard Trans >> Repair and Diagnosis >> Engine Mechanical >> Mechanical >> 7.4L V8 Engine >> Engine Specifications

Engine Specifications

GENERAL SPECIFICATIONS

Year Displ. Cu. Ins. Carburetor HP at RPM Torque (Ft. Lbs. at RPM) Compr. Ratio Bore Stroke
1981 454" 4-Bbl. ..... ..... 8.5:1 4.250" 4.000"
VALVES

Engine & Valve Head Diam. Face Angle Seat Angle Seat Width Stem Diameter Stem Clearance Valve Lift
7.4L              
  Int. 2.065" 45° 46° .031-.063" .3715-.3722" .0010-.0027" .398"
Exh. 1.720" 45° 46° .063-.094" .3713-.3720" .0012-.0029" .430"
PISTONS, PINS, RINGS

Engine PISTONS PINS RINGS
Clearance Piston Fit (1) Rod Fit Rings End Gap Side Clearance
7.4L .003-.004" .00025-.00035" .0013-.0021" 1 .010-.020" .0017-.0032"
2 .010-.020" .0017-.0032"
3 .015-.055" .005-.0065"
(1) Interference fit.
CRANKSHAFT MAIN & CONNECTING ROD BEARINGS

Engine MAIN BEARINGS CONNECTING ROD BEARINGS
Journal Diam. Clearance Thrust Bearing Crankshaft Endplay Journal Diam. Clearance Sideplay
7.4L (1)2.7481-2.7490" (1).0013-.0025" No. 5 .006-.010" 2.1990-2.200" .0009-.0025" .013-.023"
(2)2.7476-2.7486" (2).0024-.0040"
(1) Journal No. 1, 2, 3 & 4.
(2) Journal No. 5.
VALVE SPRINGS

Engine Free Length PRESSURE (LBS.)
Valve Closed Valve Open
7.4L 2.12" 84-96@1.80" 210-230@1.40"
CAMSHAFT

Engine Journal Diam. Clearance Lobe Lift
7.4L      
  Int. 1.9482-1.9492" ..... .2343"
Exh. 1.9482-1.9492" ..... .2530"