Big block Chevy (BBC) engines are one of the most popular engine families for performance builds. All common BBC engines share the same external block dimensions, which makes identification by casting number especially important.
WHERE TO FIND THE CASTING NUMBER: The block casting number on a big block Chevy is located on the driver's side of the block, behind the front motor mount. You may need to remove the motor mount or turn the wheels for access. Clean the area thoroughly before reading.
COMMON BBC BLOCK CASTING NUMBERS: 3855962: 396 or 402 ci — used in 1965–1972 Chevelle, Camaro, Corvette, and trucks. Note: the 402 was sold as a "400" in some marketing but is correctly a 402. 3963512: 427 ci — 1966–1969 high-performance applications (Corvette, Camaro, Chevelle) — one of the most desirable BBC castings 3969854: 454 ci (early) — 1970–1972 high-performance applications (LS5, LS6) 14015445: 454 ci (late) — 1973 and later production, through the truck and van era
THE "PORCUPINE" HEAD DESIGN: All BBC engines use what is commonly called a "porcupine" head design — the valves are angled in two different directions rather than aligned in a single plane. This design contributed to the BBC's excellent flow characteristics. The cylinder heads are a distinctive visual identifier of a BBC.
ALL SAME EXTERNAL DIMENSIONS: One of the great advantages of the BBC family is that the 396, 402, 427, and 454 all share the same external block dimensions. Motor mounts, bellhousing bolt pattern, and most accessories are interchangeable across the family.
For help confirming your engine or finding a replacement, contact us at 1-844-XPARTS-1 or support@expediaparts.com.
