496 Ci Engine Specs

by Manny Jeter
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The 496 Ci Engine is a top-notch Chevy engine designed for motor boats. The Big Block Chevy (BBC) model is a large, high-performing engine with 496 cubic inches. Adjustments are done by adding and tweaking different engine parts and engine dimensions. The performance of the engine can be improved upon if the adjustments are done correctly.


The 496 Ci BBC engine has a peak horsepower of 651 at 6,600 rpm and an average horsepower of 574. It has a peak torque of 585 pound-feet at 5,200 and an average torque of 562 pound-feet.


The main bearing cap has a torque of 105 pound-feet. The rod belt has a torque of 63 pound-feet. The range of torque for the head bolt is 65 to 75 pound-feet. Moly-based lubricants are recommended for these parts of the engine.

Engine Dimensions

The 496 Ci has a bore and stroke of 4.31 inches by 4.25 inches. The displacement of the engine is 496 cubic inches (hence the name 496 Ci). The compression ratio for the engine is 11 to 1. The head gasket thickness, piston deck height and total clearance measure .041, .005 and .046 inch, respectively. The piston-to-wall clearance is .004 inch. The rod bearing clearance and main bearing clearance are both .0027 inch. The 496 Ci engine's ring endgaps are .022 and .024 inch. The engine's crank endplay measures .007 inch.

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