Chevy engine block casting number lookup
The number is cast into the block at the back of the bellhousing flange. Type it and this reads back the displacement, the years it was cast and the main cap count. Where two references disagreed on the years, the row says both.
The number is seven digits. The car is years.
Buildbook keeps the rest: parts, receipts, photographs, hours and who did the work, as one Build Book that stays with the car. Free to keep, and it takes a minute to start.
Where the number is
On the bellhousing flange at the back of the block, driver's side, above the oil pan rail. Seven digits, cast in raised numerals.
On the top of the bellhousing flange at the back, or on the driver's side of the flange. Six or seven digits.
The casting date beside it, and the suffix code stamped in front of the passenger head. Those are different marks and this reads neither.
The table
All 38 blocks, printed in full. Small-blocks run 265 to 400 cu in, big-blocks 366 to 454.
265 cu in small-block, 1955, 2-bolt mains
First-year 265 block, no external oil filter boss, used in car and Corvette.
267 cu in small-block, 1979 to 1982, 2-bolt mains
Downsized 267 economy V8 block used in cars and trucks during the fuel-crisis era.
283 cu in small-block, 1957 to 1962, 2-bolt mains
Common early 283 passenger-car block.
283 cu in small-block, 1958 to 1962, 2-bolt mains
Common 283 passenger/truck block from the late 1950s-early 1960s.
283 cu in small-block, 1964 to 1967, 2-bolt mains
283 car and truck block; sources give 64-66 and 65-67, combined range shown.
305 cu in small-block, 1975 to 1979, 2-bolt mains
Also cast as a 262 in 1975 with the same number; car and truck use.
305 cu in small-block, 1976 to 1979, 2-bolt mains
Common late-70s 305 car and truck block; some Canadian-assembled heavy-duty versions had 4-bolt mains.
327 cu in small-block, 1962 to 1967, 2-bolt mains
Common 327 car and truck block; this exact casting number was reused on a different, big-block 427 truck casting from 1968-76, so check the block size before assuming.
350 cu in small-block, 1995 to 2000, cast with both 2-bolt and 4-bolt mains
Vortec truck block with roller cam and one-piece rear seal, also the basis for GM's ZZ4 and other Gen I crate motors.
350 cu in small-block, 1980 to 1985, cast with both 2-bolt and 4-bolt mains
Common early-80s 350 car and truck block.
350 cu in small-block, 1987 to 1995, cast with both 2-bolt and 4-bolt mains
Late production 350, roller or flat-tappet cam, one-piece rear main seal.
350 cu in small-block, 1968 to 1976, cast with both 2-bolt and 4-bolt mains
Common early-350 car/truck block; sources differ on 2-bolt only vs 2-or-4-bolt.
350 cu in small-block, 1967, 2-bolt mains
1967-only casting also produced as 302 (Camaro Z/28) and 327 with the same number; outintheshop cites a broader 1964-67 window for the multi-displacement group.
350 cu in small-block, 1968, 2-bolt mains
1968-only casting also produced as 302 (Camaro Z/28) and 327 with the same number; outintheshop cites a broader 1968-79 window for the multi-displacement group.
350 cu in small-block, 1968 to 1974, cast with both 2-bolt and 4-bolt mains
Multi-displacement casting; also produced as a 1969 4-bolt 302 (DZ, Z/28) and a 1969 2-bolt 327, confirmed on a NastyZ28 forum thread.
350 cu in small-block, 1969 to 1980, cast with both 2-bolt and 4-bolt mains
One of the most common SBC blocks ever cast; the same number was also used for a 1969 4-bolt 302 (Z/28) and a 1969 2-bolt 327 for trucks/industrial use.
350 cu in small-block, 1968 to 1979, cast with both 2-bolt and 4-bolt mains
Common 350 block; mortec cites a narrower 1970-76 window, outintheshop 1968-79 - a Team Chevelle forum posting of a 1972-dated example fits both.
350 cu in small-block, 1978, 4-bolt mains
One-year-only 4-bolt 350 block.
400 cu in small-block, 1970 to 1980, cast with both 2-bolt and 4-bolt mains
400 small-block, identifiable by its 3 freeze plugs per side; used in cars and trucks.
366 cu in big-block, 1968 to 1988, 4-bolt mains
Tall-deck heavy-duty truck 366, a big-block sold only as a truck engine.
366 cu in big-block, 1968 to 1985, 4-bolt mains
Tall-deck heavy-duty truck-only 366; mortec's own big-block page cites use up to 1990.
396 cu in big-block, 1965 to 1967, 2-bolt mains
Common early 396 2-bolt block; the same number was also cast as a 2-bolt 427 in 1966 and used in light-duty trucks through 1969.
396 cu in big-block, 1969, cast with both 2-bolt and 4-bolt mains
One-year 396/402 block used across the full 265-375hp Turbo-Jet range.
402 cu in big-block, 1969 to 1972, cast with both 2-bolt and 4-bolt mains
Sold as a '396' badge but actually 402 cid from 1970 on; produced in both 2- and 4-bolt main versions.
402 cu in big-block, 1970 to 1972, 2-bolt mains
Light-duty truck block; the same number was also cast as a 396 in 1968-69 and used in passenger cars in 1972.
427 cu in big-block, 1968 to 1976, 4-bolt mains
Tall-deck truck 427; mortec cites a wider 1968-85 window than nastyz28/mid-america's 1972-76 and 1968-76.
427 cu in big-block, 1968 to 1984, 4-bolt mains
Tall-deck heavy-duty truck 427.
427 cu in big-block, 1968 to 1976, 4-bolt mains
Tall-deck truck 427; distinct from the small-block 327 that shares this same casting number from 1962-67.
427 cu in big-block, 1969, 4-bolt mains
Rare aluminum ZL-1 block, one year only.
427 cu in big-block, 1968 to 1984, 4-bolt mains
Tall-deck heavy-duty truck 427.
427 cu in big-block, 1968 to 1984, 4-bolt mains
Tall-deck heavy-duty truck 427; mortec's own big-block page cites a differing 1977-90 window.
454 cu in big-block, 1991 to 1995, 4-bolt mains
Gen V 454 crate-motor block; mortec cites continued use up to Gen VI.
454 cu in big-block, 1974 to 1986
Truck-only 454; mortec cites a wider 1970-86 window than nastyz28's 1974-86.
454 cu in big-block, 1974 to 1990
Truck-only 454; mortec cites a wider 1970-90 window than nastyz28's 1974-90.
454 cu in big-block, 1973 to 1985, cast with both 2-bolt and 4-bolt mains
Very common 70s/80s 454 used across cars and light trucks; mortec cites use continuing to 1990.
454 cu in big-block, 1969 to 1971, cast with both 2-bolt and 4-bolt mains
Started life as the 1969 COPO 427 block, then carried the 1970-71 454 LS-5/LS-6; 2- and 4-bolt versions exist.
454 cu in big-block, 1973 to 1976, 2-bolt mains
Mid-70s 454 passenger and Chevelle block.
454 cu in big-block, 1971 to 1979, 2-bolt mains
Common 70s 454 car and truck block; some service/CE replacement blocks were cast with 4-bolt mains.
What this does not tell you
The casting date. That is a separate mark next to the number, a letter for the month, one or two digits for the day and one for the year. It is not decoded here.
Head, intake, crank and carburettor casting numbers. This table is blocks only.
The suffix code stamped on the front of the block, which is what actually names the engine's horsepower and application.
Whether a block has been bored, decked or sleeved. No number tells you that; a machine shop does.
- https://www.mortec.com/castnum.htm
Mortec small-block casting number list, the reference most of the hobby quotes.
- https://www.mortec.com/bbcblock.htm
Mortec big-block casting number list, 366 through 454.
- https://outintheshop.com/faq/casting/castings2.html
Out In The Shop casting tables, checked against Mortec row by row.
- https://www.nastyz28.com/
NastyZ28 block and casting references, used as the second source on big-block truck castings.
- https://midamericachevelles.com/
Mid America Chevelles casting tables, used on the 396, 402 and 454 rows.
Decoding a second-generation Camaro instead? The cowl tag decoder reads paint, interior trim, plant and build date. Hold a table we do not, or spot a row we have wrong? Write to buildbook@nanocorp.app. Corrections go in with the source named.
The heads are a separate number, cast under the valve cover. The cylinder head casting number lookup reads chamber volume, valve sizes and whether they are double humps.