Big Block Casting Numbers

1958 marked the year Chevrolet brought out the 348 C.I.D. V-8.This block was completely different from the small block Chevy, it also marked the beginning of the Big Block Chevrolet Family.The casting numbers can be found on the rear drivers side flange that meets with the transmission bell housing. Date codes can be found on either the top center of the bell housing flange or the passenger side of the block near the freeze plug locations. The famed 409 was out in 61,and at first glance can be had to distinguish from the 348.Casting numbers and date codes are the best way to find out.1961 was also the last year on the 348 in passenger cars but,was used later in trucks and buses. The 427 Mystery Motor showed up at the NASCAR tracks in 63.None of the characteristics of the 348 or the 409 were present with the new big block,like the "W" shaped heads.The first of the Mark IV engines debuted as the 396 in 65.1963 was the last year of the 409 in passenger cars,seeing limited service with some 65 full sized Chevys..The Mark IV can still be seen in service today. Available in either standard or special High Performance versions.Both versions used the same casting numbers in the early years,the difference being weather or not the block was drilled and tapped for 4 bolt main bearing caps and that is the only way to tell. Appearing in 1966,to the approval of Chevy fans and the detriment of the competition was the 427.Reaching it's zenith in 69 as an exotic all aluminum block and heads high performance engine known as the ZL-1.A hand full of Corvettes and Camaros received this option and that makes then extremely difficult to find today.Most ended up as drag racing engines and so not many survived. Mark IV engine have also been converted to truck blocks,or "tall blocks". Although essentially the same as other big block Chevys,they feature a longer crankshaft centerline to deck distance and are not normally considered desirable for passenger cars.The only way to know is to check the cast numbers. 1969 was officially the last year of the 396 but,many cars were know as 396 SS's afterward.A slightly larger bore gave the 396 a displacement of 402 CID for the 1970 model year.Many of these vehicles were marketed with 396 SS emblems on the fenders and 402 on the sticker under the hood.To make things more interesting Chevrolet marketed some of the 402 as Big Block 400 engines,like in 71.So if you have one of these engines,it's a 402 or a slightly bored out 396,you get the point.As a result Chevrolet described the big block as a 400 4 barrel and the small block as a 400 2 barrel. Appearing in 1970,the 454 boasted the highest advertised horsepower and torque ratings with the LS-6 @ 450 HP.There were plans for a LS-7 with 465 HP and they could be purchased over the counter,they were never reportedly installed in any applications. The decline of the horsepower/cubic inch wars came about with insurance rates and government regulations causing all sorts of grief.The 402/400 was discontinued after 1972 and the 454 was no longer used in passenger cars after 1976 and not installed in trucks after 1979.In 1983 Chevrolet started to install the 454 into their light and medium duty trucks.

Tell tale signs this block is a 348/409 are the raised water pump mounting bosses (1) and the relieved surface area on the deck (2)

Different Chevrolet body configurations required the clutch counter shaft stud hole to be machined into different locations on the. Pre 64 blocks and certain late model blocks do not have the second hole so they are not recommended for early V-8 Chevelles and Nova

Some of the big blocks had machined surfaces above the timing chain cover flange where the factory would stamp the V.I.N. of the vehicle thet engine was installed into.

The engine blocks intended for the truck applications featured a longer distance from the crankshaft centerline to the deck surface.

This engine was intended for a car.

Casting #	CID	Year	Model Applications	Comments
340220	427	68-76	Truck
361959	454	73-75	Chevelle
361959	454	73-76	Passenger
361959	454	75-85	Truck	Light Duty
364776	427	68-84	Truck	Heavy Duty
364779	366	68-88	Truck	Heavy Duty
473478	427	68-84	Truck	Heavy Duty
3732811	348	58	Passenger
3751872	348	58	Passenger
3755011	348	59-61	Passenger
3771705	348	59-61	Truck & Replacement
3782870	427	68-76	Truck
3788068	409	62	Passenger
3795623	409	61	Passenger
3798962	348	62-65	Truck & Replacement	Has X on Block
3830814	409	63	Passenger	Has X on Block
3844422	409	64	Passenger	Has X on Block
3855961	396	65-67	Passenger	325 HP,2 bolt mains
3855961	427	66	Corvette	390,425 HP,2 & 4 bolt mains
3855961	396	66	Chevelle	325,360,375 HP
3855961	396	68-69	Truck	Light Duty
3855962	396	65	Corvette,Passenger	425 Hi-Perf
3855962	396	65	Chevelle	Z16 Hi-Perf
3855962	396	66	Passenger	375 HP,Hi-Perf
3855962	396	66	Chevelle	360 HP,4 bolt main
3857655	348	62-65	Truck	Has X on Block
3857656	409	65	Passenger	Has X on Block
3869942	427	66	Corvette & Passenger	390,425 HP
3902406	396	67	Chevelle	2 & 4 Bolt Main
3902406	396	67	Camaro	2 & 4 Bolt Main
3902406	396	67	Passenger	2 & 4 Bolt Main
3902466	396	66-69	Passenger,Chevelle
3902466	396	67-69	Camaro
3902466	396	68-68	Nova
3904351	427	67	Passenger	385 HP
3904351	427	67	Corvette	390,400,430,435 HP
3904354	366	66-67	Truck
3916319	366	68-85	Truck	Heavy Duty
3916321	427	67	Corvette	Late 1967
3916321	427	68	Passenger	2 & 4 Bolt Main
3916321	427	68	Corvette	390,400,430,435 HP
3916323	396	68	Chevelle	2 & 4 Bolt Main 325,350,375 HP
3916323	396	68	Camaro	325,350,375 HP
3916323	396	68	Nova	325,350,375 HP
3916323	396	68	Passenger	2 Bolt Main
3925521	366	68-85	Truck	Heavy Duty
3935439	427	68	Corvette	430,435 HP
3935439	427	69	Passenger	385,425 HP
3935439	427	69	Corvette	390,400,430,435 HP
3935440	396	68	Pass,Chevelle,Camaro,Nova
3937724	366	68-85	Truck	Heavy Duty
3937726	427	68-84	Truck	Heavy Duty
3955270	427	69	Corvette	390,400,430,435 HP
3955270	427	69	Passenger	385,425 HP
3955272	396	68-69	Truck	Light Duty
3955272	396	69	Pass,Chevelle,Camaro,Nova
3955272	402	70-72	Truck	Light Duty
3955274	366	68-85	Truck	Heavy Duty
3955276	427	68-84	Truck	Heavy Duty
3963512	427	68-69	Passenger	385,425 HP
3963512	427	69	Chevelle,Camaro	COPO (Central Office Production Order)
3963512	427	69	Corvette	Late 69
3963512	454	70	Corvette,Passenger	360,390 HP
3963512	454	70	Chevelle	LS-6 450 HP
3963512	454	70-71	Pass,Chevelle, Monte Carlo
3963512	454	71	Corvette	365,425 HP
3963513	454	73-75	Chevelle
3963513	454	73-76	Passenger
3968854	396	68-69	Truck	Light Duty
3968854	396	68-69	Pass,Chevelle,Camaro,Nova
3968854	402	70-72	Pass,Chevelle,Camaro,Nova
3968854	402	70-72	Truck	Light Duty
3968852	366	68-85	Truck	Heavy Duty
3968854	402	69-72	Pass,Chevelle,Camaro	4 bbl Carb,2 & 4 Bolt Main
3968854	402	70	Nova	2 & 4 Bolt Main
3968854	400/402	70-72	Truck	2 & 4 Bolt Main
3969858	427	68-84	Truck	Heavy Duty
3995623	409	61	Passenger	all
3999289	454	72	Corvette	270 HP
3999289	454	72-75	Chevelle
3999289	454	72-76	Passenger
3999289	454	73-79	Truck
3999290	396	68-69	Truck	Light Duty
3999290	400/402	70-72	Truck
3999290	402	70-72	Truck	Light Duty
3999290	402	72	Pass,Chevelle,Camaro,Nova
3999290	402	72	Pass,Chevelle,Camaro,Nova	4 bc
3999293	366	68-85	Truck	Heavy Duty
3999293	454	73-75	Pass,Chevelle
3999294	427	68-84	Truck	Heavy Duty
6272177	402	72-73
14015445	454	75-87	Truck	Light Duty