Should I extend the drive shaft?
 

I've already completed the 6" BDS lift on my 2 door 4x4, 2005 Blazer. I notice that there is now only about 2" of the splined end of the yolk shaft that actually gets into the transfer case on the rear drive shaft. It's been like that for the the better part of a year and I haven't had any problems yet but should I get the drive shaft extended anyway? If so, how much should I extend it, assuming the rear end may now have a bit more suspension travel than stock?

you could try 6 degree shims...maybe??
i have a 5 inch lift and wondered the same thing...

Six degree shims.
 

I had actually never heard of these so I did a bit of a search on them. I guess the idea is that the shims would align the differential output flange / yolk with the drive shaft thereby adding some length to the shaft assembly and providing more insertion depth to the spline yolk into the transfer case. Is that correct?
Seems like that would take a lot of stress off of the rear U-joint as well. I'll try and get more information on this. Thanks for the advice.

yup no problem, i bought mine at suspensionconnection (think thats right)
were cheap and worked for me. i had a slight driveline vibration problem.

Miscellaneous - 6 degree axle shims 2" wide w/3/8" center pins (pair)

i think thats what i bought...have to double check me on the width.