Slant 6 engine boss decoding

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NorthernMainer

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Caribou, Maine
Hey folks, curious as to when my 225 was produced. A lot of online searching led me to write down the numbers behind the coil pack. What I saw (picture attached) is 6225R 2 5 28. I cant seem to find any kind of breakdown as to what these mean. All I know is the 6225 means it's a 225.

According to the 10,000 day calendar this engine was built Saturday June 29th 1968.. that's if the 2528 is the date of manufacture.

I guess my reason for wanting to know is in 1976 they went from the forged crank to the nodular iron crank. The door tag in the car says the car itself was produced 6/1976 so I would think that would give the engine an earlier 76 production date.

Any help is greatly appreciated!

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Pretty certain an "E" stamping accompanies all cast-crank 225's, and for certain the X & Maltese cross means the crank has multiple undersize journals from the factory.
 
Pretty certain an "E" stamping accompanies all cast-crank 225's, and for certain the X & Maltese cross means the crank has multiple undersize journals from the factory.

Thankfully mine doesn't have the E! the undersized journals don't worry me too much.
 
There are other stamps to read.

What is stamped for the partial VIN?

What is the casting date on the block?

6/1976 would be fairly late in the 1976 model year which began in 1975.
 
There are other stamps to read.

What is stamped for the partial VIN?

What is the casting date on the block?

6/1976 would be fairly late in the 1976 model year which began in 1975.

I'm not 100% sure where the partial vin is, but I did have someone break down the code in that picture I posted. Was told the block was built febuary 5th 1976, and was the 28th block that day. I will try to google where the partial vin, and casting date is, I know the engine is original to the car. We bought it from the original owner. The car has 58,000 miles on it.
 
So it's definitely the original engine to the car. The numbers on the rear boss are C6223489. The last of the numbers match my vin. I guess the only way I'll know if it's forged or cast crank is pulling the oil pan, and measuring the connecting rod width. Cast are a little under an inch wide at the bottom, while forged are a little over an inch at the bottom.
 
When You get that late in eng. ID stampings, they started including single character codes for base/mid/high line optioned cars. I'm fairly certain all cast crank units have the
"E" stamped directly after"225", .....what kind of vehicle are we working on here? Due to popularity, the A-bodies overlapped the F-bodies a bit,...so a late '76 build date
wouldn't be a shocker, as that was the final model year for them.
 
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