* Specific Crankshaft: Different manufacturers might have slightly different specifications.
* Main Bearing Caps: The number of main bearing caps varies slightly depending on the application.
* Hardware: The type of main bearing cap bolts (e.g., studs, bolts) affects the tightening procedure.
* Repair Manual: The most reliable information will be found in a factory service manual or a reputable rebuild manual *specific* to the year, model, and engine code of your big-block Chevy.
General Principles (Always verify with your manual):
While a precise sequence cannot be given without knowing the specifics of your engine, the general principle for tightening main bearing caps is to follow a cross-pattern or star pattern. This ensures even clamping force and prevents distortion of the crankshaft block. A common pattern might look like this (for a four-bolt main engine, adjusting the pattern for more or fewer bolts as needed):
1. Tighten one bolt to a low initial torque
2. Go diagonally across to the opposite bolt and tighten to the same low initial torque
3. Tighten the remaining bolts in a cross pattern in stages, gradually increasing the torque per step.
Crucial Point: Never attempt this without a properly sourced torque sequence and torque specifications from a reputable source (a service manual for your exact engine is essential). Incorrect torque can lead to crankshaft damage, bearing failure, and catastrophic engine problems.
