What drive shaft to use

[juddss]

Just totaled my 04 cts V and thinking of buying it back and installing the LS6 and T56 in my 70 suburban. Also may add the 2010 Cts v blower I have on top of it.
My question is what driveshaft are you guys using the stock one and just changing the length of it. I have the the driveshaft from my Cts v so was thinking of bringing it to a local driveline shop and having the front yolk adapted onto the stock driveshaft.
I wonder how much my stock driveshaft can handle??