Is 4.5 months prior to car production considered date code correct for engine block?

[4mulas]

What make a block date code correct? How much before car production would be considered date code correct? 69 B body

Thanks!

 

[nitro_rat]

Depends on what plant it was built at and what engine it is. It could be anywhere from weeks to years depending on the backlog of available castings at any given time. The 1966 run of Hemi blocks lasted well into 1968 production IIRC. So YMMV depending on when and where your car was built.

To be most accurate you would want to find a car built at the same plant around the same time as yours, or even better, a handful of them. Now depending on your combination someone here may know but we would need more information. For example, all A12 cars were scheduled for the same production day and all the engines likely came from the same batch of castings so the date range for those engines is likely common knowledge.

 

[cosgig]

I had a 71 383 HP block that was cast in 68 and was assembled in 1970 for the 71 model year, so I’m sure a couple months before your SPD is perfectly acceptable.

 

[Kern Dog]

I have a 11-9-69 440 block that came from a 71 Chrysler 300.

 

[kiwigtx]

Three months is the rule of thumb for most parts - rarer parts may be a lot longer gap.

 

[69Coronetrt]

For example, all A12 cars were scheduled for the same production day and all the engines likely came from the same batch of castings so the date range for those engines is likely common knowledge.

69 A12s had two different SPDs with production ranging over about four-five months.

I don't have personal access to the details but given the number of engines assembled and the range of A12 engine assembly dates, I don't think research would support the blocks coming from the same batch of castings.

 

[69Coronetrt]

What make a block date code correct? How much before car production would be considered date code correct? 69 B body

Thanks!

A stated earlier, it depends on the application.

With a high volume block like a 318 or 383, inventory turned over much quicker than other assemblies likely leading to a more narrow window than something like Hemi cars where a casting could be 1-2 years ahead of the SPD.

What are we talking about? /6 Coronet? 318 Charger? 383 HP Super Bee? 6bbl Road Runner? Hemi GTX?