I have the engine out of my 1971 Cutlass and started looking at casting dates.
The car was assembled in Arlington Texas the first week of May 1971. (The body plate says "05A". I don't know how it could ever be proven -- or disproven -- but is believed to have been assembled on Thursday, May 6. For the sake of discussion, we'll go with that date.)
In Julian dates, that means the car would have been assembled the 126th day of the year.
The block casting is "76". March 17 seems to leave plenty of time to machine and ship it before assembly.
The heads say "119". That would be April 29. That seems like an awful short lead time to be in a car just seven days later.
The engines were all assembled in Lansing then shipped to the GMAD plants, correct?
I'm just the second owner of the car and I've had it since 1993. The original owner said the heads "were re-done", but I never asked for specifics. I always assumed they were the original #7 heads, just "re-done". Now I'm wondering if they are original.
How do these compare with others' casting dates versus final assembly?

 

It's amazing what some casting dates will be for cars of that era. For instance, I have a '68 4-4-2 convertible that my parents bought brand new. When I did the restoration back in 2007, I documented all the original parts I had for the car, including but not limited to the engine block, heads, and all the way to the power steering gear box and cover to it. A lot of the parts were within a couple of months of the build date (first week of April 1968 which was April 1-5, a Monday through Friday) but there were anomalies. The block, which has a VIN derivative stamped into the correct spot that agrees with the car's VIN, had a casting date of "304" which is 11/1/67, quite a distance (5 months) from the first week of April 1968. The only thing I can surmise is that perhaps there had been a problem with that particular block and it was taken out of line and remedied before being put back in line for assembly. The heads were right where one would anticipate them to be at "64" and "67" (March 4 and March 7). The differential and cover to it also ha mid-March dates. The seat belts were all in the mid-February to mid-March time frame. The steering column even has an early March 1968 date stamped into an underside location. But here's another kicker: the steering box was dated "92" and its cover "95" (April 1 & 4, respectively). That's right there at the production date of the car. What I'm guessing here is that assembly of my '68 probably started towards week's end and was finished at the beginning of the second week of April 1968. Also, parts didn't go on the shelf in order by date as I understand. They just went on the shelf and assembly people took whatever was next and put it on the car.

So, again in my opinion, what you are seeing is not out of any kind of order. Generally speaking, the word around is that parts usually have a date of within three months to a week or two before assembly. However, there are exceptions and, in the NCRS/Corvette world, they generally accept a part dated within 6 months of assembly and there are even exceptions to that rule. And I'm sure the block to my '68 is another one of those exceptions to the three month rule as I know it is original to the car.

Randy C.