I know for my 83 drive train to fit into my 78 chassis I had to have the shaft shortened. I know you should have a little in and out play with the shaft, even though these have IRS the whole system is only supported by rubber mounts so there is always going to be the need for parts to move.

 

if the early car is like the later cars, the differential is held stationary, it does not move. i dont see why anything more than expansion of the drivetrain from heat would be needed---maybe 1/4 inch.

 

You only have to have the DS shortened (to my knowledge) to make the T5 fit (83 drivetrain). It should be really really tight.

mnelson_260z

 

last time I did a engine /tranny swap, parts sat around for a while, and when I went to put in the driveshaft, I had three of them around but couldn't remember which was which. They were different lengths.You absolutely do need some play, more than a quarter inch; when you hit a big bump or otherwise really stress the car, things wiggle around a bit, both the motor and the rear end.....I am sure that z-cars had different length drive shafts and if you are able to get ahold of an assortment at the pick n pull then you can find what you need. If, like me, you don't have a good pick n pull around, then go ahead and follow the advice of the driveshaft shop and have it shortened by the amount they recommend. I'm sure somebody here will know which cars had which length shafts, too.....But don't try to run it with a tight fit; something has to give....tranny, rear end, or shaft......
My guess is that the driveshaft out of a 280 Z is a little shorter....

 

It was only around 50 bucks to have it shortened too, no big deal.

 

my 78 driveshaft was as long at the one that came out of a 79.....

 

If you want a shorter driveline, the ones out of a 70-71 are shorter than the 72's by an inch or so. I'm pretty sure that they have a bunch of them at Z Specialties if you haven't fixed the problem already. You might be able to do a partial trade with them, doesn't hurt to ask.