Drive shaft measurement

I have absolutely no drive train in my 68 at all other than the 8 3/4. The engine is on the stand in the garage and I haven't even picked up a 727 yet, but if I knew approximately how long the shaft is then I could go over to this guy's house and measure, not that I need it right now but the price is right and I am in my collecting parts mode. I bought this car with no drive train because I have a 340, but right now that's all I have.
Bob