When sourcing a Chevy Small Block (SBC), you must first identify the generation (Gen I, II, or LS-based) and the displacement (e.g., 350, 383 stroker, or 400). Key technical factors include the block material (cast iron vs. aluminum), the main bolt pattern (2-bolt vs. 4-bolt mains) for high-performance durability, and the crankshaft type (forged steel vs. cast iron). Ensure the compression ratio aligns with your intended fuel type and that the cylinder head intake port volume matches your RPM requirements.