FICM recal / speedo recal

[F350R]

I have an 04 CC LB dually 72K miles that I just put a new to me 06 FICM ($300) in today. What a relief, that alone brought my mileage up 4 mpg, at least on the lieO meter. The new FICM holds 48.5v all day long although it does have the FICM killer program in it, but not for long. I want to have my OEM FICM retuned then mate it up with the good power supply and reinstall it.

My question is which ECM holds the speedo cal? I have 245x70x19.5 tires that are 33" so I had to have one of the ECM's recalibrated but I don't know which one holds that info? It still seems to be shifting correctly so I am assuming its not in the FICM. I should have brought my GPS with me today that would verify that the speedo is correct.

Mike