Oldsmobile block identification

[Bob cacy]

I have 1971 cutlass with different engine and would like to know the year of my motor. The numbers on it are 395558 2, like  to know what each number means. 

[61polara]

That looks like a casting part number on the intake manifold.  What is needed is the VIN number stamped on a pad somewhere on the block.  

[joe_padavano]

That is the casting number. It is the same number used for ever Olds 350 block cast from the 1968 to 1976 model years. Only the VIN derivative stamp on the driver's side of the block near the #1 spark plugs will tell you the year.

[lump]

The above info is basically correct. However, there is a casting DATE code on most GM blocks, intakes, exhaust manifolds, heads, etc. This code is generally considered more reliable than stamped in codes (at least for very-desirable high performance components), since there is little danger of anyone counterfeiting a raised cast code. 

[joe_padavano]

5 minutes ago, lump said:

The above info is basically correct. However, there is a casting DATE code on most GM blocks, intakes, exhaust manifolds, heads, etc. This code is generally considered more reliable than stamped in codes (at least for very-desirable high performance components), since there is little danger of anyone counterfeiting a raised cast code. 

 

Sorry, but the VIN derivative stamp is the ONLY foolproof way to find the MODEL YEAR of the block. This isn't a Chevy motor.

[Bob cacy]

Thanks I’ll check the block under the number one plug. I took out the the original distributor and replaced it with electronic ignition, would that change what type of spark plug I use or just go with the year of the block. 

Edited August 14, 2019 by Bob cacy (see edit history)

[lump]

21 hours ago, joe_padavano said:

 

Sorry, but the VIN derivative stamp is the ONLY foolproof way to find the MODEL YEAR of the block. This isn't a Chevy motor.

Joe, 

I'm certainly no expert on Oldsmobiles, and I may be about to learn something worthwhile here. But if true, this information is a little bit shocking to me. 

 

The fact is that cast engine components, like heads, intakes, exhaust manifolds, and blocks, were usually cast in GM plants where most other GM cast components came from....Chevy, Buick, Cadillac...and Oldsmobile. At least as far as I knew. The casting numbers and casting dates were obviously not created to help future restorers and hot rodders to identify components; rather they were put on the components as a part of GM's attempt at improving quality control (as you likely already know). Thus, if GM started to receive a large number of warranty claims on the same kind of components on recently-sold new cars (cylinder heads for 1968 Buicks, just making up an example), they would examine the failed parts---noting the casting numbers (which would refer them back to original blueprints), date codes (which helped them figure out when the component was made, so they could match up the failed part with actual production documentation), and even the actual time of day the component was produced (those familiar little cast-in raised-letter clockfaces). Then, HOPEFULLY they could identify a common failure, and either redesign the part or tighten up production standards at a certain plant on certain shifts. 

 

Now, again, I am definitely not an expert on Oldsmobile casting numbers, but it sure does seem unusual that GM would have broken their protocol for Oldsmobile engine blocks (especially since we know that Oldsmobile intakes, exhaust manifolds, etc, did indeed carry casting dates on them). I will contact a couple of Oldsmobile experts, if I can recall their contact info, and ask for some insights. 

 

Again, I hope I won't seem accusatory, disagreeable, or arrogant. I have no Oldsmobile blocks lying about to go and check. This one just catches me by surprise, because after all those hours I spent in GM factories researching the books I have written, I really had a strong impression that GM's quality control system for cast iron and cast aluminum parts was corporate-wide. 

 

Best wishes to all. ----Lump

[Bob cacy]

57 minutes ago, lump said:

Joe, 

I'm certainly no expert on Oldsmobiles, and I may be about to learn something worthwhile here. But if true, this information is a little bit shocking to me. 

 

The fact is that cast engine components, like heads, intakes, exhaust manifolds, and blocks, were usually cast in GM plants where most other GM cast components came from....Chevy, Buick, Cadillac...and Oldsmobile. At least as far as I knew. The casting numbers and casting dates were obviously not created to help future restorers and hot rodders to identify components; rather they were put on the components as a part of GM's attempt at improving quality control (as you likely already know). Thus, if GM started to receive a large number of warranty claims on the same kind of components on recently-sold new cars (cylinder heads for 1968 Buicks, just making up an example), they would examine the failed parts---noting the casting numbers (which would refer them back to original blueprints), date codes (which helped them figure out when the component was made, so they could match up the failed part with actual production documentation), and even the actual time of day the component was produced (those familiar little cast-in raised-letter clockfaces). Then, HOPEFULLY they could identify a common failure, and either redesign the part or tighten up production standards at a certain plant on certain shifts. 

 

Now, again, I am definitely not an expert on Oldsmobile casting numbers, but it sure does seem unusual that GM would have broken their protocol for Oldsmobile engine blocks (especially since we know that Oldsmobile intakes, exhaust manifolds, etc, did indeed carry casting dates on them). I will contact a couple of Oldsmobile experts, if I can recall their contact info, and ask for some insights. 

 

Again, I hope I won't seem accusatory, disagreeable, or arrogant. I have no Oldsmobile blocks lying about to go and check. This one just catches me by surprise, because after all those hours I spent in GM factories researching the books I have written, I really had a strong impression that GM's quality control system for cast iron and cast aluminum parts was corporate-wide. 

 

Best wishes to all. ----Lump

T

 

57 minutes ago, lump said:

Joe, 

I'm certainly no expert on Oldsmobiles, and I may be about to learn something worthwhile here. But if true, this information is a little bit shocking to me. 

 

The fact is that cast engine components, like heads, intakes, exhaust manifolds, and blocks, were usually cast in GM plants where most other GM cast components came from....Chevy, Buick, Cadillac...and Oldsmobile. At least as far as I knew. The casting numbers and casting dates were obviously not created to help future restorers and hot rodders to identify components; rather they were put on the components as a part of GM's attempt at improving quality control (as you likely already know). Thus, if GM started to receive a large number of warranty claims on the same kind of components on recently-sold new cars (cylinder heads for 1968 Buicks, just making up an example), they would examine the failed parts---noting the casting numbers (which would refer them back to original blueprints), date codes (which helped them figure out when the component was made, so they could match up the failed part with actual production documentation), and even the actual time of day the component was produced (those familiar little cast-in raised-letter clockfaces). Then, HOPEFULLY they could identify a common failure, and either redesign the part or tighten up production standards at a certain plant on certain shifts. 

 

Now, again, I am definitely not an expert on Oldsmobile casting numbers, but it sure does seem unusual that GM would have broken their protocol for Oldsmobile engine blocks (especially since we know that Oldsmobile intakes, exhaust manifolds, etc, did indeed carry casting dates on them). I will contact a couple of Oldsmobile experts, if I can recall their contact info, and ask for some insights. 

 

Again, I hope I won't seem accusatory, disagreeable, or arrogant. I have no Oldsmobile blocks lying about to go and check. This one just catches me by surprise, because after all those hours I spent in GM factories researching the books I have written, I really had a strong impression that GM's quality control system for cast iron and cast aluminum parts was corporate-wide. 

 

Best wishes to all. ----Lump

 

23 hours ago, joe_padavano said:

That is the casting number. It is the same number used for ever Olds 350 block cast from the 1968 to 1976 model years. Only the VIN derivative stamp on the driver's side of the block near the #1 spark plugs will tell you the year.

 

On 8/12/2019 at 9:05 PM, 61polara said:

That looks like a casting part number on the intake manifold.  What is needed is the VIN number stamped on a pad somewhere on the block.  

Thanks I’ll check the block under the number one plug. I took out the the original distributor and replaced it with electronic ignition, would that change what type of spark plug I use or just go with the year of the block. 

[joe_padavano]

53 minutes ago, lump said:

Again, I hope I won't seem accusatory, disagreeable, or arrogant. I have no Oldsmobile blocks lying about to go and check. This one just catches me by surprise, because after all those hours I spent in GM factories researching the books I have written, I really had a strong impression that GM's quality control system for cast iron and cast aluminum parts was corporate-wide. 

 

Best wishes to all. ----Lump

 

No offense taken. Oldsmobile blocks have a three digit date code cast near the distributor. That is simply a Julian date, so it tells you the day of the year cast but not the year. Model year info comes from the VIN derivative. Oldsmobile also has other numbers cast in various places on the block, but no one has been able to prove that they tie to an actual calendar year, and no documentation defining them has been found. For example, above that date code is a single digit that some people claim is represents the year, but the digit isn't the actual number of the year. It starts out with "1" for each type of block (330, ,350, 400, 425, 455) and increments upward over time. For example, since the 455 blocks were first cast in calendar year 1967 for the new 1968 cars, people claim that "1" represents the first calendar year of production (1967), 2=68, 3=69, etc. Unfortunately, this does not always correspond to model year of the car (a "3" block with a late calendar year Julian date code would presumably have been used in a 1970 model year car, but it was found to have the VIN derivative of a 1969 car). Oldsmobile has also, at various times, used a digit like this to denote mold codes for casting molds, and has incremented the numbers based on detail mold revisions (similar to rolling the revision letter on a blueprint when it is modified). Personally, I find that a more believable premise, but again, no documentation has surfaced. Here's an example of that Julian date code and the other number that could be the year or could be the mold revision.

 

[Bob cacy]

Here’s a picture of the stamp under number one plug. 

[joe_padavano]

2 minutes ago, Bob cacy said:

 

 

This is not a factory VIN derivative stamp, obviously. This is either a rebuilt motor with the rebuilder's stamp or this block was originally used in a non-automotive application. Olds sold a lot of motors for stationary (industrial) and marine use in the late 60s and early 70s.

[Bob cacy]

Thanks for the help joe I appreciate it. 

[a1elcamino]

On 8/13/2019 at 9:12 PM, Bob cacy said:

 Joe is the most correct in this thread as saying the way to find out the year is to use the pad I.D. at the number one plug, but that is not always the case, therefor the only way we where to I.D. an engine was a paper sticker on the oil fill tube. Yes they deteriorated, Yes they were pressure washed off and yes they faded and finally yes they were changed out at the dealers when swapping engines for warranty and non warranty job tickets. In the later years every thing was recorded by vin # as to what RPO (Regular Production Option) the vehicle was built with, also they always had build sheets if you could find one. I was an Oldsmobile technician from 1983 till they pulled the plug In April 2004 and performed service until 2009. I was one of the first to hold title the Oldsmobile Master Technician status and was awarded yearly on my performance through Oldsmobile. We were an elite group of Technicians back then. No tickey, no washey  wasn't just a phrase for the cleaners.

 

 

 

Thanks I’ll check the block under the number one plug. I took out the the original distributor and replaced it with electronic ignition, would that change what type of spark plug I use or just go with the year of the block.