Chevy cylinder head casting number lookup

Under the valve cover, cast into the top rail between the two centre exhaust ports. Take the cover off; you will not read it from outside. Six to eight digits.

On the valve cover rail, or on the end of the head near the corner bolt. Six to eight digits, cast in raised numerals.

The hobby says a 461, an 882, an 049. Those are the last three digits of the full number, and they are not unique — 462 was cast under at least five different numbers, and 291 is both a small-block camel hump and a big-block rectangle port. Typing three digits here shows every head it could be.

The casting date beside it, and the block casting number at the back of the bellhousing flange. Those are different marks and this reads neither.

283, 327 small-block, 1957 to 1967, iron, 59cc chamber

valves 1.72 / 1.50

The first modern small-block head, and the pattern the whole double-hump family grew out of. Careful with the shorthand: 842 is also a big-block L88 aluminium head.

Sources differ: Both references agree on the years and the engines; only Speedway prints the 59cc chamber.

327 small-block, 1962 to 1967, iron, 62cc to 65cc chamber

Fuelie, the first double hump, valves 1.94 / 1.50

The original camel-hump casting. No accessory bosses on the ends, which is how an early double hump is told from a later service head.

Sources differ: Speedway reads 65cc. Mortec and the Team Chevelle measurements read 62 to 64cc.

327 small-block, 1964 to 1966, iron, 60.5cc to 62cc chamber

Fuelie, double hump, valves 1.94 / 1.50, and 2.02 / 1.60 reported on later production

The head the hobby means when it says fuelie: standard on the fuel-injected 327 Corvette engine. 160cc intake port, no accessory bosses. The earlier 3782461X is a different casting with bigger runners, and typing the whole number is the only way to tell them apart here.

Sources differ: A forum measurement reads 60.5cc against Mortec's 62cc, and later castings are reported with 2.02 / 1.60 valves where the 1964 to 1966 specification is 1.94 / 1.50.

283, 327 small-block, 1960 to 1963, iron, 62cc to 64cc chamber

Double hump, the X variant, valves 1.94 / 1.50

Larger 172cc intake runners against 160cc on the plain 461, and rarer. The X is cast into the head with the number.

Sources differ: Chevy Hardcore calls the X chamber slightly larger than the 461; Mortec lists both at 62cc.

302, 327, 350 small-block, 1966 to 1967, iron, 62cc to 64cc chamber

Double hump, valves 1.94 / 1.50

Replaced the 461. No accessory bosses.

Sources differ: Speedway reads 62cc in 1966 and 63cc in 1967; Mortec reads a flat 64cc.

350 small-block, 1967, iron, 63cc chamber

Double hump, valves 1.94 / 1.50

One of at least five castings whose last three digits are 462, which is why the shorthand on its own does not settle which head is on the bench.

302, 327, 350 small-block, 1967 to 1969, iron, 63cc to 64cc chamber

Double hump, valves 2.02 / 1.60

The big-valve camel hump, no accessory bosses, around a 165cc intake port. Not to be confused with the big-block 3964291, also called a 291.

Sources differ: Speedway gives 63 to 64cc, Mortec a flat 64cc.

327, 350 small-block, 1968, iron, 64cc chamber

Turbo 292, valves 2.02 / 1.60

Became the Pro Stock small-block head of the 1970s and the basis of the Crane Fireball.

Sources differ: Chevy Hardcore is the only catalogue source. Forum discussion of the 292 against the 461X corroborates the port and the valve size but not the single year.

302, 350 small-block, 1968 to 1970, iron, 64cc chamber

Double hump, with accessory holes, valves 2.02 / 1.60

The same head as the 291 with the accessory bosses drilled on the ends, which is what most people actually find.

350 small-block, 1969 to 1970, iron, 64cc chamber

Double hump, with accessory holes, valves 2.02 / 1.60

The other common accessory-hole camel hump, alongside the 186.

350 small-block, 1969 to 1970, iron, 76cc chamber

valves 1.94 / 1.50, commonly opened up larger

Not a double hump. Open chamber, and it takes a bigger valve than it left with, which is why circle-track racers of the era used it.

350 small-block, 1970, iron, 64cc chamber

Double hump, LT-1, valves 2.02 / 1.60

The 1970 LT-1 350 head, the 370 horsepower engine.

350 small-block, 1970 to 1979, iron, 64cc chamber

Double hump, LT-1 over the counter, valves 2.02 / 1.60

LT-1 head with accessory holes, and sold over the parts counter for years afterwards — so a 492 on a car is not evidence the car had an LT-1.

Sources differ: One magazine flow test read the 492 intake port near 159cc against 165cc measured on other camel humps.

350, over the counter small-block, 1970 to 1979, iron, 64cc chamber

Turbo head, valves 2.02 / 1.60, angle plug

The service-counter angle-plug head out of Smokey Yunick's Indy work. Out of the box it beat fully ported 461X heads.

307, 350 small-block, 1972 to 1973, iron, 75cc chamber

valves 1.94 / 1.50

Low compression, the daily-driver head, and reissued for decades on Goodwrench crate engines — so a 993 can be much newer than 1973.

350, 400 small-block, 1974 to 1980, iron, 76cc chamber

valves 1.94 / 1.50

The smog-era 350 and 400 head, poured in enormous numbers, and the one most often found bolted to a running seventies car. A 76cc chamber is what makes those engines low compression.

Sources differ: Mortec gives the chamber but no valve size; 1.94 / 1.50 is the commonly quoted street specification rather than a catalogued one.

350 small-block, 1986 to 1987, aluminium, 58cc chamber

L98 Corvette, valves 1.94 / 1.50

The tuned-port Corvette aluminium head, and the basis of the later ZZ4 crate engine head.

350 small-block, 1987 on, iron, 64cc chamber

valves 1.94 / 1.50

Truck and crate head, the last big iron design before the Vortec. The centre intake bolts are angled, so it wants its own intake.

350, LT1 small-block, 1992 to 1997, aluminium, 53cc chamber

Gen II LT1, ports 175cc intake, 68cc exhaust

Reverse-flow cooling: the water reaches the heads first. Not interchangeable with a first-generation small block. Both references catalogue this head by its port volumes rather than its valve diameters, so no valve size is printed here.

350, LT1 small-block, 1994 to 1996, aluminium, 53cc chamber

Gen II LT1, ports 175cc intake, 68cc exhaust

One of several LT1 castings across the Gen II run. Catalogued by port volume rather than valve diameter, so no valve size is printed here.

350, LT1 small-block, 1996, aluminium, 53cc chamber

Gen II LT1, ports 175cc intake, 68cc exhaust

The last of the LT1 castings. Catalogued by port volume rather than valve diameter, so no valve size is printed here.

350, LT4 small-block, 1996 to 1997, aluminium, 52cc to 54.4cc chamber

Gen II LT4, ports 195cc intake, 68cc exhaust, angle plug

Bigger ports and angle plugs than the LT1 head it replaced. Catalogued by port volume rather than valve diameter, so no valve size is printed here.

Sources differ: OnAllCylinders reads 52cc, Mortec 54.4cc.

350, LT4 small-block, 1996, aluminium, 52cc chamber

Gen II LT4, ports 195cc intake, 68cc exhaust

The second LT4 casting. Catalogued by port volume rather than valve diameter, so no valve size is printed here.

Sources differ: OnAllCylinders lists 1992 to 1997; Mortec lists 1996 alone. The 1996 overlap is the part both agree on.

350, Vortec L31 small-block, 1996 on, iron, 64cc chamber

Vortec, valves 1.94 / 1.50

The Vortec head the hobby swaps onto older small blocks for the 64cc chamber and the 170cc port. It needs its own intake and self-aligning rockers, and the heavy-duty version has a harder exhaust seat.

Sources differ: A forum claim that the 906 flows about 20 percent better than the 062 is contradicted by the NastyZ28 Vortec guide, which says the two make the same power.

350, Vortec L31 small-block, 1998 on, iron, 64cc chamber

Vortec, valves 1.94 / 1.50

The Vortec casting most often bought off the shelf, and the same specification as the 906.

Sources differ: Same relative-flow argument as the 906: a forum puts the 906 ahead on intake flow, the NastyZ28 guide says they make the same power.

396, L35 325 horsepower big-block, 1965 to 1966, iron, 97cc chamber

Oval port, closed chamber, valves 2.19 / 1.88

Among the earliest big-block castings, off the 325 horsepower 396. The smallest chamber of the oval ports, so the highest compression.

Sources differ: 97.2cc against 97cc, a rounding difference.

396, L37 and Z-16 375 horsepower big-block, 1965, iron, 109cc chamber

Rectangle port, closed chamber, valves 2.19 / 1.88

The 1965 375 horsepower 396 and the Z-16 Chevelle head. Rare enough that a pair runs into the thousands, which is reason to read the casting date beside the number too.

Sources differ: Chevy Hardcore prints a 1.99 inch exhaust valve where Mortec and NastyZ28 read 1.88 for closed-chamber rectangle ports of the year.

396, 427, L78 375 horsepower big-block, 1965 to 1967, iron, 109cc chamber

Rectangle port, closed chamber, valves 2.19 / 1.88

The L78 head, the solid-lifter 375 horsepower engine.

427, L88 and L89 big-block, 1967, aluminium, 106.8cc to 107cc chamber

Rectangle port, closed chamber, valves 2.19 / 1.88

Genuine L88 and L89 aluminium head with the Winters snowflake foundry mark. Valuable, and reproduced, so the mark and the casting date are worth as much as the number.

Sources differ: 107cc against 106.8cc, a rounding difference.

396, 427, L88 and L89 big-block, 1968 to 1969, aluminium, 107cc chamber

Rectangle port, closed chamber, valves 2.19 / 1.88

The later L88 and L89 aluminium head. Shares the 842 shorthand with an early iron small-block head, which the three digits cannot tell apart.

427 L88 and ZL1, 454 LS6 big-block, 1969 to 1971, aluminium, 118cc chamber

Rectangle port, open chamber, valves 2.19 / 1.88

One casting number on the 1969 ZL1 and again on the 1971 LS6 — two very different engines, so the number alone does not date the head.

396, 402, 427, 454 big-block, 1969 to 1970, iron, 101cc chamber

Oval port, closed chamber, valves 2.06 / 1.72

One of the most asked-about big-block numbers. Large-hex and small-hex spark plug versions both exist.

Sources differ: 100.9cc against 101cc, a rounding difference.

396, 402, 427, 454 big-block, 1969 to 1972, iron, 109cc chamber

Rectangle port, closed chamber, valves 2.19 / 1.88

The big-valve closed chamber, and it kept going on crate engines after 1972. Careful: 291 is also the shorthand of the small-block camel hump 3917291. They are unrelated heads.

402 LS3, 454 LS5 big-block, 1971 to 1984, iron, 113cc chamber

Oval port, open chamber, valves 2.19 / 1.88

One of the first open-chamber big-block heads, out of the 1969 to 1971 transition, and a big-valve oval port, which is unusual.

Sources differ: Chevy Hardcore and NastyZ28 put it on the 1971 402; Mortec extends the 454 use to 1984. The two are describing different applications rather than contradicting each other.

454 LS6 big-block, 1971, iron, 118cc chamber

Rectangle port, valves 2.19 / 1.88

The iron LS6 head, the 450 horsepower 454.

Sources differ: Chevy Hardcore and Mortec call 3994026 an open chamber. NastyZ28's table calls it closed and lists a companion 3994025 as the open one. Look at the chamber itself to settle it.

454 big-block, 1970 on, iron, 118cc chamber

Rectangle port, open chamber, valves 2.06 / 1.72

A very common service replacement, used on some Mark IV crate engines.

Sources differ: Both references read 2.06 / 1.72 even though the port is rectangular — against the rule of thumb that rectangle port means big valve. Do not assume the valves from the port shape on this one.

454 big-block, 1973 to 1985, iron, 113cc to 118cc chamber

Oval port, open chamber, valves 2.06 / 1.72

The common 454 oval port, cross-shopped forever against the 236 and the 049. Forum consensus is that it likes 2.19 and 1.88 valves once it is opened up, and will carry serious power ported.

Sources differ: NastyZ28 reads 113cc, Mortec 118cc.

454 big-block, 1975 to 1987, iron, 113cc to 120cc chamber

Oval port, open chamber, valves 2.06 / 1.72

The other common 454 oval port, the 781's near twin.

Sources differ: Mortec reads 120cc, NastyZ28 and forum measurement 113cc.

396, 402, 454, 366 and 427 truck big-block, 1968 to 1984, iron

Oval port, open chamber, valves 2.06 / 1.72

With its pair, the 330865, the plentiful truck head. Everywhere at a swap meet, and cheap for that reason.

Sources differ: Neither reference prints a chamber volume; the open chamber is read off the port and the years. Measure it.

396, 402, 454, 366 and 427 truck big-block, 1968 to 1984, iron

Oval port, open chamber, valves 2.06 / 1.72

The 330864's pair, and the same head for practical purposes.

Sources differ: Neither reference prints a chamber volume; the open chamber is read off the port and the years. Measure it.

454, Mark IV service big-block, 1969 on, aluminium, 118cc chamber

C-port rectangle, open chamber, valves 2.19 / 1.88, or 2.06 / 1.72

The service and aftermarket aluminium replacement, also sold as a bare casting, so a 077 is often a fresh head rather than an old one.

Sources differ: NastyZ28 and Mortec read 2.19 / 1.88, Chevy Hardcore reads 2.06 / 1.72. Both are printed here because a valve size is worth measuring before you buy.

454 Bowtie, Mark IV, Gen V and Gen VI big-block, 1984 on, aluminium, 105cc on the first design, 115cc on the second chamber

Bowtie raised runner, valves 2.19 / 1.88

One casting number and two chambers: the first design runs to 1996 at 105cc, the second from 1996 at 115cc. Which one you have changes the compression ratio by about a point.

454, Vortec 7400 L29 big-block, 1996 on, iron, 100cc chamber

Vortec 7400, closed chamber, valves 2.06 / 1.72

The 7.4 litre truck head. Non-adjustable rockers, which matters if you are putting an older cam under it.

454, Vortec 7400 big-block, 1998 on, iron, 100cc chamber

Vortec 7400, closed chamber, valves 2.06 / 1.72

The later Vortec 7400 casting, same specification as the 279.

496 and 502, Vortec 8100 big-block, 2001 on, iron

Vortec 8100, valves 2.06 / 1.72

The 8.1 litre Gen VII truck head — a different engine family from the Mark IV under it, so very little swaps across.

Sources differ: Neither reference states a chamber volume for this casting.

Searched constantly as a 454 oval-port head, and forum consensus reads it at 113cc, functionally the same casting as the 781 and the 236. Nobody we checked prints its full seven-digit casting number, so there is nothing here to match against a number cast in iron. The 336781 and 346236 rows below are the two heads it is always compared with.

A 305 head, and enthusiasts rate its chamber above the 416 for flame travel. Owner measurements land at 53 to 55cc with 1.84 / 1.50 valves. Only forum threads name it, and only by the three digits, so the full casting number is unconfirmed.

The other common 305 smog head, read at about 58cc with 1.84 / 1.50 valves and a squarer chamber than the 601. Same problem: discussed everywhere by the shorthand, catalogued nowhere we could check by its full number.

Associated by the hobby with the long-running 462624 smog-era 350 and 400 casting, which ran 1975 to 1986 at 76cc with three different valve sizes across the run. We could not confirm the digits match on a second reference, so it is out of the table.

Listed by Mortec as a 1974 to 1975 350 head, 76cc, 2.02 / 1.60 — a big-valve open chamber, which would make it the pick of the smog-era castings. One reference only, so it is not in the table.

3927185, a high-production low-compression 307, 327 and 350 head at 70cc with small 1.72 / 1.50 valves. Despite the numbering it is not a double hump. One reference only.