http://www.mortec.com/diagram1.gif
The diagram above shows where each of the casting identifiers is located on the engine. (1) shows the location of the HEAD CASTING NUMBERS and the HEAD CASTING DATE located under the valve covers, in the rocker arm valley. (2) shows the position of the BLOCK CASTING DATE on the rear ledge of the block near the bell housing mounting surface. If you have an early big block or a late model smallblock, the BLOCK CASTING DATE may be on the passenger side of the engine block, (see 2A), instead of the rear ledge of the block. Some smallblock blocks may also have the BLOCK CASTING DATE on the driver's side of the block. (3) indicates the position of the BLOCK CASTING NUMBER. Later blocks may also have the size of the engine displacement in liters listed at (3). (4) indicates the position of the ENGINE ASSEMBLY DATE/SUFFIX CODE and partial VIN code information on the front of the block. (5) on the rear flange of the block, on the drivers side near the oil filter pad, is an alternate block location for some VIN codes. (6) indicates the sides of the block where some blocks may have the size of the motor indicated in cubic inches or in liters. The last three numbers of the block casting number may also be repeated in this location.

http://www.mortec.com/diagram1.gif
The diagram above shows where each of the casting identifiers is located on the engine. (1) shows the location of the HEAD CASTING NUMBERS and the HEAD CASTING DATE located under the valve covers, in the rocker arm valley. (2) shows the position of the BLOCK CASTING DATE on the rear ledge of the block near the bell housing mounting surface. If you have an early big block or a late model smallblock, the BLOCK CASTING DATE may be on the passenger side of the engine block, (see 2A), instead of the rear ledge of the block. Some smallblock blocks may also have the BLOCK CASTING DATE on the driver's side of the block. (3) indicates the position of the BLOCK CASTING NUMBER. Later blocks may also have the size of the engine displacement in liters listed at (3). (4) indicates the position of the ENGINE ASSEMBLY DATE/SUFFIX CODE and partial VIN code information on the front of the block. (5) on the rear flange of the block, on the drivers side near the oil filter pad, is an alternate block location for some VIN codes. (6) indicates the sides of the block where some blocks may have the size of the motor indicated in cubic inches or in liters. The last three numbers of the block casting number may also be repeated in this location.

There are three block casting number types to look for: the block CASTING NUMBER, the block CASTING DATE and the ENGINE ASSEMBLY DATE/SUFFIX CODE.
BLOCK CASTING NUMBER
The block casting number on smallblock and big block Chevy V-8 motors is located on a ledge found at the rear of the block, most often on the driver's side. This ledge is below the deck of the block and the ledge forms the mating surface between the block and the transmission bellhousing. Some of the later model blocks have the casting number on the passenger side of this ledge. The number itself can have 6, 7 or 8 numeral digits. They might look like this "361959" or "3970010" or "14015445". The block casting numbers do not have any letters in them. There are sometimes individual letters found on blocks like "GM" or "CFD" for the Central Foundry Division, but they are not part of the block casting number. Also some of the later blocks have the size of the motor shown in liters. You may see a "5.0" (305) or "5.7" (350) cast on the rear ledge of a smallblock or a "7.4" on the side of a big block 454. On the side of some later blocks the last three digits of the block casting number are cast into the block, but these are difficult to see when the engine is in a vehicle.
http://www.mortec.com/cast2.gif http://www.mortec.com/cast13.gif
http://www.mortec.com/cast17.gif http://www.mortec.com/cast14.gif

There are three block casting number types to look for: the block CASTING NUMBER, the block CASTING DATE and the ENGINE ASSEMBLY DATE/SUFFIX CODE.
BLOCK CASTING NUMBER
The block casting number on smallblock and big block Chevy V-8 motors is located on a ledge found at the rear of the block, most often on the driver's side. This ledge is below the deck of the block and the ledge forms the mating surface between the block and the transmission bellhousing. Some of the later model blocks have the casting number on the passenger side of this ledge. The number itself can have 6, 7 or 8 numeral digits. They might look like this "361959" or "3970010" or "14015445". The block casting numbers do not have any letters in them. There are sometimes individual letters found on blocks like "GM" or "CFD" for the Central Foundry Division, but they are not part of the block casting number. Also some of the later blocks have the size of the motor shown in liters. You may see a "5.0" (305) or "5.7" (350) cast on the rear ledge of a smallblock or a "7.4" on the side of a big block 454. On the side of some later blocks the last three digits of the block casting number are cast into the block, but these are difficult to see when the engine is in a vehicle.
http://www.mortec.com/cast2.gif http://www.mortec.com/cast13.gif
http://www.mortec.com/cast17.gif http://www.mortec.com/cast14.gif

BLOCK CASTING DATE
The block casting date indicates when the block itself was cast in the foundry. This date does not indicate when the motor was assembled and then later placed into the vehicle at the factory. The block casting date is usually found on the rear ledge of the block on the passenger side, but some later model blocks have the casting date on the driver's side of the rear ledge. Some of the early big blocks made in the Sixties have the block casting date located on the passenger side of the block near the freeze plug holes. On these, if the early big block is in the car you will have to get under the motor to see the casting date. Do it while the car is on a lift. The casting dates look something like this "E 12 7". The "E" stands for the month of the year with "A" being the month of January, "B" being the month of February and so on thru the letters to December. In this case the "E" stands for the month of May, the fifth month of the year and the fifth letter of the alphabet. The "12" stands for the 12th day of the month. The "7" is the year of the decade. Now unfortunately this could be '57, '67, '77, '87 or '97 depending on which part you are looking at. Some casting dates have both the year of the decade and the decade itself. They look like this "E 12 77", meaning May 12, 1977. The fun starts when you have a casting date from the first nine days of the month that look like this "D 2 6". Does that stand for April 2,1966 or does it stand for April 26th and the year is missing or hard to see? You have to look closely and carefully to be sure.
http://www.mortec.com/cast3.gif http://www.mortec.com/cast7.gif

BLOCK CASTING DATE
The block casting date indicates when the block itself was cast in the foundry. This date does not indicate when the motor was assembled and then later placed into the vehicle at the factory. The block casting date is usually found on the rear ledge of the block on the passenger side, but some later model blocks have the casting date on the driver's side of the rear ledge. Some of the early big blocks made in the Sixties have the block casting date located on the passenger side of the block near the freeze plug holes. On these, if the early big block is in the car you will have to get under the motor to see the casting date. Do it while the car is on a lift. The casting dates look something like this "E 12 7". The "E" stands for the month of the year with "A" being the month of January, "B" being the month of February and so on thru the letters to December. In this case the "E" stands for the month of May, the fifth month of the year and the fifth letter of the alphabet. The "12" stands for the 12th day of the month. The "7" is the year of the decade. Now unfortunately this could be '57, '67, '77, '87 or '97 depending on which part you are looking at. Some casting dates have both the year of the decade and the decade itself. They look like this "E 12 77", meaning May 12, 1977. The fun starts when you have a casting date from the first nine days of the month that look like this "D 2 6". Does that stand for April 2,1966 or does it stand for April 26th and the year is missing or hard to see? You have to look closely and carefully to be sure.
http://www.mortec.com/cast3.gif http://www.mortec.com/cast7.gif

Thanks ~~~ BUT ~~~ I can't take the credit for it, I obtained it from another sorce ~ ie
http://www.mortec.com/
Alot of good info there, such as
HOLLEY CARB INFORMATION (http://www.mortec.com/carbs.htm)
HOLLEY TUNING TIPS (http://www.mortec.com/carbtip1.htm)
CHEVY V-8 BLOCK AND HEAD CASTING NUMBERS (http://www.mortec.com/castnum.htm)
CHEVY V-8 CASTING NUMBER LOCATIONS (http://www.mortec.com/location.htm)
CHEVY V-8 BORE AND STROKE LIST (http://www.mortec.com/borstrok.htm)
CHEVY V-8 CRANKSHAFT JOURNAL SIZES (http://www.mortec.com/journal.htm)
CHEVY V-8 CRANKSHAFT CASTING NUMBERS (http://www.mortec.com/cranks.htm)
CHEVY V-8 NOTES (http://www.mortec.com/notepg1.htm)
GM/PERFORMANCE PARTS (http://www.mortec.com/sfam2.html)
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