Gears & Axles - Does anyoe know the correct driveshaft length for my setup? PLEASE HELP!

Here is the deal, I have a 02 f-body, I already removed the stock rear end and installed a Moser 9". Next weekend I will be swapping my 4L60 out with a 4L80. I want to have my shaft length correctly cut this week so I can have everything installed next weekend.

So what is the correct center to center of the U-joint bores for my new setup? If the 4L60 and the 4L80 are the same length it looks like I need a center to center length of 42 1/8th". Is this correct?

Thanks

are you using the stock driveshaft and having it shortened?

the 4l80e is about 3/8" longer than the 4l60e btw.

No, I am having one built by PST. I think the Moser 9" makes it needing to be longer. We are going to go with a 42" Center to center and see what happens.