Hi,
No luck on a short block for this. The # you have 68411234AA is a later 2018+ 6.4 , Its cost would be
4,757.50
+ 750.00 Core Charge
+ Est. 400.00 freight shipping
Availability is OK but it would still be about 2 weeks before you would see it.
If you want me to look into the earlier 6.4 let me know, I am not sure what changed over time.
- Benny