Big Block Cylinder Head Casting Numbers

With the level of performance being the defining factor in identifying big block Chevy cylinder heads it's important to understand some very key factors in different designs. The very first big block for Chevy was the 348 back in 1958. And as a result of Chevy's engineers we now have what is referred to as "big block" and "small block". The early heads used pretty much the same heads on both the standard and the performance version of the 348. The main difference in power was from little tricks like a higher lift cam and triple carb or "three deuce" set ups.
  Fast forward to 1961. The 409 hit the street and a year later you could get a 425 horsepower version with a dual quad set up and a decent set of high performance heads to go with it. The 396 or Mark IV hit the scene in 65 and featured both screw in studs and factory guide plates on both their standard and high performance versions. The difference between the 348 or 409 and the new engine was easily noted at first glance just by the shape of the head. The earlier heads had a "W" shape unique to the 348 and 409.

  Now-a-days guys restoring Chevys that had big blocks in them are looking for "correct" heads. This means original for their specific application. And they search very hard for these heads. They are getting harder and harder to find due to so many sets getting modified for racing applications and such and as a result are very expensive. Mark IV big blocks had two different types of cylinder heads, square and oval. The large square port was used on the high performance engines and the oval port was used on lower and medium performance applications. The square port version also got came with solid lifters and 4 bolt main blocks. There was also an "open chamber" and a "closed chamber" head. Both types of chambers were used for either performance or standard engines. One of the most rare cylinder head for the big block chevy is the 375 horsepower 396 and the ZL-1 427 aluminum head.

  With the valve covers and intake manifold on 99% of BBC heads look the same. Casting numbers and date codes are found with the valve covers off. Cast letters that are raised will say things like "Special High Perf","Pass" and even "Truck" denote their specific application. And as with the small block, they did away with the compression washer for the 1970 model year. Just be mindful when you are looking at a set of cylinder heads from 69-72 that you can effectively I.D. the plug that goes into it.

Cast #	CID	Year	Model	Comments
330864	366,427,454	70-81	Truck
330864	400,402,396	70-81	LT Truck	Oval Port
330865	400,402,454	70-76	LT Truck	Oval Port
330865	366,427	70-84	HD Truck
336765	427,454	73-84	Truck
336781	454	73-76	Pass,Chevelle,Corvette	Oval Port
336781	454	73-85	Truck
343771	366,427,454	68-84	HD Truck
343772	366,427,454	76-84	HD Truck	Oval Port
346236	454	75-76	Passeneger	Oval Port
346236	454	75-87	LT Truck
353049	400,402	70-73	LT Truck	Oval Port
353049	454	73-76	Truck	Oval Port
353049	454	73-76	Pass,Chevelle,Corvette	Oval Port
473328	366	68-85	HD Truck	Oval Port
3732791	348	58	Passenger
3758379	348	59-61	Passenger
3759256	348	58	Passenger
3767738	348	59-61	Passenger
3781147	348	60-61	Passenger	Hi Perf
3795586	409	61	Passenger	360 HP
3814690	409	62-64	Passenger	Hi Perf
3819333	348,409	62-65	HD Truck
3830817	409	63-65	Passenger	STD Perf,340 hp
3837731	409	63	RPO Z11	Special Hi Perf
3852583	409	65	Passenger	400 HP
3856206	396	65	Passenger	Oval Port
3856208	396	65	Corvette	425 hp,sq port,hi perf
3856208	396	65	Pass,Z16 Chevelle	425 hp,sq port,hi perf
3856213	366	66-82	Truck	Oval Port
3856260	396	68
3872702	427	66	Corvette	390 hp,Oval Port
3872702	396	66	Pass,Chevelle	Oval Port
3873858	396,427	66	Passenger	Sq Port,Hi Perf
3873858	427	66	Corvette	425 hp
3873858	396	66	Chevelle	Sq Port,Hi Perf,375 hp
3873858	396	67	Camaro	Sq Port,Hi Perf,375 hp
3876875	427	77-85	Truck	Oval Port
3904390	427	67	Corvette	390,400 hp
3904390	396	67	Pass,Chevelle	Oval Port
3904391	396	67	Chevelle,Camaro	Sq Port,Hi Perf,375 hp
3904391	427	67	Corvette	Cast Iron,early 67,435 hp
3904392	427	67	Corvette	Aluminum,L88,L89,hi Perf
3904393	366	66-68	Truck	Oval Port
3909802	396	67	Pass,Camaro,Chevelle	Oval Port
3909802	427	67	Corvette,Passenger	Oval Port,385,390 hp
3917215	427	68	Corvette,Passenger	Oval Port,390,400 hp
3917215	396	68	Camaro,Nova	Oval Port
3917215	396	68	Passenger,Chevelle	Oval Port
3917219	366,427	68-85	HD Truck	Oval Port
3919840	427	67	Corvette	Cast Iron,late 67,435 hp
3919840	396	68-69	Camaro,Nova,Chevelle	Sq Port,Hi Perf
3919840	427	68-69	Pass,Corvette	Cast Iron,Sq Port,Hi Perf
3919842	427	68	Corvette	Aluminum,L88,L89,Hi Perf
3919842	396	68-69	Camaro,Nova,Chevelle	Aluminum,L89,Hi Perf
3919842	427	69	Corvette	Aluminum,L89,Hi Perf
3931063	396	68-69	Pass,Camaro,Chevelle,Nova	Oval Port
3931063	396	68-69	Truck	Oval Port
3931063	427	69	Pass,Corvette	390,400 hp,Oval Port
3931063	400,402	70-72	LT Truck	Oval Port
3933148	366,426	68-84	HD Truck	Oval Port
3933148	369	69	Passenger	Oval Port,2 bc
3933149	427	68-76	Truck	Oval Port
3946074	427	69	Corvette	Aluminum,L88,ZL1,Hi Perf
3936074	427	69	Camaro	Aluminum,ZL1,Hi Perf
3936074	454	71	Corvette	Aluminum,LS6,425 hp,Hi Perf
3964290	402	70	LT Truck	Large & Small Plugs
3964290	454	70	Corvette	Large & Small Plugs,390 hp
3964290	402	70	Pass,Camaro,Chevelle,Nova	Large & Small Plugs,Oval Port
3964290	400	70	Passenger	Oval Port
3964291	402	70	Camaro,Nova,Chevelle	375 hp,L78 Sq Port,Hi Perf
3964291	454	70	Chevelle	450 hp,LS6,Sq Port,Hi Perf
3935198	396	68-69	Truck	Oval Port
3975950	366,396,427	68-70	HD Truck	Oval Port
3986133	366,427,454	68-85	HD Truck	Oval Port
3986136	366,427,454	68-84	Hd Truck	Oval Port
3993820	454	71	Corvette	365 hp
3993820	400	71-72	Chevelle	Oval Port
3993820	402	71-72	LT Truck	Oval Port
3993820	454	71-72	Pass,Chevelle	Oval Port
3993820	402	71-72	Pass,Camaro,Chevelle	Oval Port
3994026	454	71	Chevelle	LS6,Sq Port,Hi Perf (RARE)
3994026	454	71	Corvette	LS6,425 hp
3999241	402	72	Pass,Camaro,Chevelle	Oval Port
3999241	454	72	Chevelle	Oval Port
3999241	454	72	Corvette	270 hp
6272292	454	70-75	Pass,Chevelle,Corvette	Oval Port
6272292	402,454	71-72	Pass,Chevelle	Oval Port
6272292	454	71-71	Truck	Oval Port
14092359	427	86-88	Truck	Oval Port
14092360	454	85-88	Truck	Oval Port