PCM Diagnostics & Tuning - Firing order?

I am looking to change a 99 SS OS to a 02 OS and while doing this I noticed that the firing orders between the 2 year models are different. Has anyone else noticed this and why would GM do this the 99 order is cylinders 31872654 and the 02 is 18726543?

I dont know which one to use.

Can someone tell me why?

Both those are the same, look at it carefully:) Does it matter that the 3 makes a difference? I wouldn't think so

i guess for some reason they have cylinder 3 in the cell to fire 1st on the 99 file and cylinder 1 fire 1st on the 02.

I guess it doesnt matter which one is first in the cells as long as the order in which the cylinders are right

Thanks over looked that one

On the first one, start at 1, and you will see that they are the same.