Unknown Block Identification

[John M.]

I am trying to identify an engine block for an owner that has it in his 1962 Corvette. I thought I might have the info, but it is beyond what I have. For that reason I now turn to those of you who I know are knowledgeable in this area.

First of all, this block is not an 870 block and is NOT original to the 1962 Corvette. This is a GM block #3959512. Numbers on the block stamp pad in front of the right side head are CE122087 V0805XCB (or as close as can be determined and as I was told).

Can anyone identify this block application, the horsepower, and decode the stamp pad numbers?

Thanks, & Save the Wave .................

JG Mattson

[Joe L.]

Re: Unknown Block Identification

I am trying to identify an engine block for an owner that has it in his 1962 Corvette. I thought I might have the info, but it is beyond what I have. For that reason I now turn to those of you who I know are knowledgeable in this area.

First of all, this block is not an 870 block and is NOT original to the 1962 Corvette. This is a GM block #3959512. Numbers on the block stamp pad in front of the right side head are CE122087 V0805XCB (or as close as can be determined and as I was told).

Can anyone identify this block application, the horsepower, and decode the stamp pad numbers?

Thanks, & Save the Wave .................

JG Mattson

John-----


GM #3959512 was a SERVICE-only block used for 4" bore applications, usually 327 cid but some may have been 350 cid. The SERVICE-only origin is further confirmed by the "CE" coding and "XCB" suffix code. However, I can't find a reference for the XCB code so I can't tell you more about the engine.

[John H.]

Re: Unknown Block Identification

The CE122087 says it's a 5/50 warranty replacement block built at Flint V-8 in 1971; that's all the "CE" number will tell you. Are there any numbers stamped on the machined block bottom surface where the starter bolts up like the photo below?

[John M.]

Re: Unknown Block Identification

Thanks for the reply Joe. I had a hunch you would be one to step up to the plate with an answer. Now would you define "SERVICE BLOCK" for me and those like me that would like to ask the same question but will not for fear of looking ........... well, uninformed?

Save the Wave ............. JGM

[John M.]

Re: Unknown Block Identification

Thanks for the reply John. I'll have to check with the owner to see if any numbers are stamped in this location. What would be the significance of any numbers in this machined area?

Save the Wave ............ JGM

[John H.]

Re: Unknown Block Identification

Thanks for the reply John. I'll have to check with the owner to see if any numbers are stamped in this location. What would be the significance of any numbers in this machined area?

I've noticed these stampings on several "CE" blocks - appears to be a month/day date code; the "CE" stamp only identifies the year.

[Cecil L.]

Re: Unknown Block Identification

Quoting from a Chevrolet Dealer Service Information Bulletin dated 14 April, 1969:

The first letter will designate the GM division which produced the engine. C-Chevrolet L-Oldsmobile K-Cadillac B-Buick P-Pontiac

The second letter will designate the type of unit "E" engine or "T" transmission. The number following the letter will designate the model year "9" for 1969. The last five digits specify the service replacement unit sequence number. The group of numbers to be used by Chevrolet manufacturing plants [for engines, CRG] are as follows:

Flint motor plant (L-6 engines) 00001 to 19999
Flint V-8 engine plant 20000 to 49999
Tonowanda motor plant 50000 to 79999

Example: Number CE900175 designates Chevrolet engine - 1969 year, and the 175th unit produced for service at the Flint motor plant.

This numbering system applies to service engine assemblies, partial engines, fitted cylinder cases, cylinder cases, transmission assemblies and transmission cases.

The reference further states that all Hydra-Matic transmissions are coded "H" regardless of division produced for.

[Joe L.]

Re: Unknown Block Identification

Thanks for the reply Joe. I had a hunch you would be one to step up to the plate with an answer. Now would you define "SERVICE BLOCK" for me and those like me that would like to ask the same question but will not for fear of looking ........... well, uninformed?

Save the Wave ............. JGM

John------


The "XCB" would identify the engine IF we had some way of de-coding it. This series of three character suffix codes beginning with "X" also denotes a SERVICE engine (i.e. an engine not installed in a PRODUCTION vehicle at a vehicle assembly plant).

[John M.]

Re: Unknown Block Identification

The CE122087 says it's a 5/50 warranty replacement block built at Flint V-8 in 1971; that's all the "CE" number will tell you. Are there any numbers stamped on the machined block bottom surface where the starter bolts up like the photo below?

John

There are no numbers stamped on the machined surface where the starter bolts up.

On this block there is a cast clock face on the bellhousing flange next to the distributor hole.
Sometime during the 1964 model year, a casting clock code was added to some Saginaw blocks to indicate the hour of the shift in which the part was made. This clock code is approximately two inches in diameter, and is usually found at the rear of the block, near the casting number. The clock is made up of ten dots, each representing one hour of a specific shift. There is a second dot outside the circle, which represents the beginning if a ten-hour shift. The Saginaw foundry usually operated in two shifts, the first from 7:00AM to 4:00PM, and the second shift from 4:00PM until midnight. Parts cast at the start of the shift would have the single clock hand pointing toward the double-dot hour position. Parts cast four hours into the shift would have the hand pointing to the fourth dot clockwise from the double-dot The screw head in the center of the clock designated the shift. A flat-head screw indicated first shift, and a round-head screw indicated the second shift
Does the presence of this clock face indicate that this block is a Saginaw block, or were clock faces also used at Flint and Tonawanda?

There is also the cast number F250 on the right side bellhousing flange of this block. This number has screw heads on both ends, one a flat-head & one a round-head. I believe this to be the casting date, and if so would read it as June 25, 1970. Do you agree with this?

The heads on this block have the cast numbers G40 & G80 with cast screw heads on either side of each. This should be the casting date of each head, which I would read as July 4, 1970 and July 8, 1970. Not far off from the F250 cast on the block.

You stated above that the CE1220087 indicates this block was built (assembled?) at Flint in 1971. Could this block have been cast at Saginaw in mid 1970 (as it looks to be indicated) and assembled at Flint sometime in 1971? Was there that much elapsed time between casting and assembly of blocks rated as Service blocks?

Numbers from the past can be a mystery and certainly challenging to decode and figure out as time has moved on and spawned new minds with new ways to confuse us and hobbyists of the future.

Thanks for all your help with my many questions. I really appreciate your input, as well as all others who have responded or will respond.

Save the Wave............ JGM

[John H.]

Re: Unknown Block Identification

Does the presence of this clock face indicate that this block is a Saginaw block, or were clock faces also used at Flint and Tonawanda?

There is also the cast number F250 on the right side bellhousing flange of this block. This number has screw heads on both ends, one a flat-head & one a round-head. I believe this to be the casting date, and if so would read it as June 25, 1970. Do you agree with this?

The heads on this block have the cast numbers G40 & G80 with cast screw heads on either side of each. This should be the casting date of each head, which I would read as July 4, 1970 and July 8, 1970. Not far off from the F250 cast on the block.

You stated above that the CE1220087 indicates this block was built (assembled?) at Flint in 1971. Could this block have been cast at Saginaw in mid 1970 (as it looks to be indicated) and assembled at Flint sometime in 1971? Was there that much elapsed time between casting and assembly of blocks rated as Service blocks? JGM

The "casting clock" was used at both the Saginaw and Tonawanda foundries.

The casting date format indicates a Saginaw casting, June 25, 1970. Service-only castings could sit around for a while, as they were only used when Service ordered blocks (short or fitted) or engine assemblies, and Saginaw probably poured them in batches.

[John M.]

Re: Unknown Block Identification

Thanks guys, I appreciate all the information. I will inform the individual who sought my help on identifying this engine block, give you all credit, and teach him how to use this forum.

Save the Wave ........ JGM