Small block Chevy (SBC) block casting numbers are one of the most reliable ways to identify the engine you have — or confirm what's in an engine you're looking at. Here are the most common numbers.
WHERE TO FIND THE CASTING NUMBER: The block casting number is located on the driver's side of the block, between the #3 and #5 cylinder positions (on the left bank, in the middle of the block). It may be partially obscured by the motor mount, wiring, or grime. Clean the area with a rag or parts cleaner before trying to read it.
COMMON SBC BLOCK CASTING NUMBERS: 3970010: 350 ci — 1969–1979 (one of the most common SBC castings; used across many applications) 14010207: 350 ci truck block — 1987 and later (common in later truck and van applications) 3914678: 302 or 327 ci — 1967–1969 (used in both displacements; confirm bore size) 3956618: 350 ci LT1 — 1970–1972 (the first LT1, not to be confused with the Gen II LT1 of the 1990s)
IMPORTANT NOTES: • The same casting number can be used across multiple displacements. A 3.875" bore is 327 ci; a 4.000" bore from the same casting is 350 ci. If you need to know the exact displacement, measure the bore or confirm the crank stroke. • Casting numbers tell you when and where the block was made — they do not necessarily tell you what the engine was assembled as. An engine can be bored or stroked differently from its original spec. • The casting date (a separate stamped code on the block) can also help narrow down the production era.
For help confirming your engine or finding the right replacement, contact us at 1-844-XPARTS-1 or support@expediaparts.com.
