Can someone please tell me exactly where on a 1968 GS350 I would look to find the numbers to compare to determine whether or not the original engine is still in the car?

Thanks for your help...David G.

David, the last 8 characters of the VIN will be stamped on the engine block as the engine serial number. It should be in the form of 8H100001. This number decodes as 8=1968 model, H=GM plant (H is Flint, Mich.), 100001=vehicle production sequence no. (first car is 100001). The number should be stamped on the front of the block, left side, near top, where head attaches. If the last 6 digits match the VIN, the car has its original engine.

There is another less-specific number on the engine, the production code number. It give the year, size and HP data. For 68 350s it was stamped into the block in the area on the left side between the front two spak plugs and the exhaust manifold. It is in the form of ab123. The letters PP indicate a 68 4bbl 350.

These numbers were stamped in some different locations on the block depending on the year and displacement.

Thanks for the info Todd.

Todd, I found the # on the distributor side under a bit of grime. It looks like it is 41H107551 or 41H107331. The tops of the 5's or 3's didn't really make an impression, so not sure, but that's just the sequence it came off the line, right? Where does the 41H place this engine originally? My VIN is 434378K108773. Thanks, David G.

David, The motor looks like it come from a later model car. The beginning 4 is a division identifier code for Buick. This digit was added to engine id's about the time GM started installing one division's engines in the other divisions' cars.

The one indicates a car/engine built in 1971 or 1981. Only cars exported to Canada recieved the 350's in 81. Do you have the part numbers from any of the other original accessories such as the distributor or the starter? Too, we need the engine production code number.

The H indicates the engine was built in the Flint, MI plant. The K on your VIN shows it came from the Kansas City, MO plant. The H would be expected on a Buick engine, even if the car was assembled in one of the other plants.

So far the only other numbers I've been able to find are on the back of the intake. There is B-1238647-2 and B / 7, and 350 on the lower back of the intake. Don't see the engine production code where it should be for a 68. Where else might I look for it? Doesn't look like the original distributor either. I'll have to get a look at the starter later. Will let you know if I can find anything.

David, the production code number would be in the same spot on a 71 as the 68. Other places to look are on the front surface of the block, right (passenger) side and around the left (driver) side near the serial number. Also try the other ledges on the block faces where the heads attach, near the spark plugs/exh manifold. In any case, the number will be stamped into the block. One other thought is to find the alternator part number. Does it have an EGR valve? That would put it at 73 or later.

Too, back to the earlier post, yes the illegible 3s or 5s are part of the last 6 digit number that indicates the order off the assemly line.

[This message has been edited by TODD (edited 09-30-2001).]

Todd, I just had a conversation with the owner that did just about all of the restoration and rebuild work on the car from 1995-2000. Turns out the 350 came from a 1972 Skylark. Would a 72 Skylark have an engine coded 1971? He also swapped in a posi rear-end, electronic ignition, and a Carter AFB Competition Series carb. Says he put $13,000 actual cash into it, signed it over to his kid for HS graduation, only to have him trade it for a 67 Buick and give $200 to boot. And to think I got it for $6500...thanks for your efforts to identify this for me.

Todd,
No luck finding the production code number yet. But near the #1 spark plug there is a 72 in fairly large letters on the left head right by the front of the engine, but on the side. I emailed an inquiry to Buick, and after about a week they emailed me that it is not a Buick engine!! Are you positive that the 4 in 41H107551 indicates Buick? Or maybe they just couldn't figure it out, so said it's not? Anyway, I'm about ready to garage the car til next spring. Maybe then I'll pull some items out of the way so I can get a better look at the block and heads.

David, the year codes on the VIN and engines go by model year, not calendar year. This means a 72 car and engine would have 2 as the year digit even if it was made in late 71. My bet would be the 72 car somehow had a 71 block installed in it. Or the car was a 71 and was misidentified as a 72 (could have had a 72 front clip installed ?).

There is an example drawing in the 72 Buick shop manual to show where to find the engine serial number. The number used in the example is 42H100001. The 75 shop manual shows the same drawing, but the number is 45H100001. The 79 shop manual spells it out clearly that the 4- prefix denotes a Buick-built engine. I could buy that the engine came out of something other than a Buick; say another GM car or even a large boat.

The H (Flint) plant is the old original Buick plant. Don't know of any other GM division ever building engines there. Like you, I wonder about the experience level of the employee writing the e-mail reply. Looks like they didn't supply any additional information as to what kind of engine it could be.

One last thought, is there a number stamped into the harmonic balancer? We might can at least confirm that as a Buick 350 part number.

I replied back to the Buick internet response team, and a supervisor emailed back an admission that their records only go back to 1972, so they couldn't help me at all. It SOUNDS like this should be a 71 Buick 350 for sure. Would a 71 Skylark have valve covers without the 350-4 decals that a GS would have? On a related subject, there is a rebuilt TH350 on this GS, with about a 7 digit number on it that starts with 86...does this indicate a 1986 tranny? Also, where can I find the HP and torque ratings for a stock 71 Skylark 350-4? And do you know where I can id the intake casting #? I found a site listing GS intake casting #'s, but not Skylark.

I'll try to check on the harmonic balancer # soon. Don't have much free time for the GS these days. -dg-

[This message has been edited by dg-gs350 (edited 10-08-2001).]

[This message has been edited by dg-gs350 (edited 10-08-2001).]