I had my mechanic install an 83 280zx 5 speed tranny (3.90) and an R200 diff out of the same car into my 70 Z. I believe the driveshaft was from the same car (driveshaft has 83 280zx written on it in marker). The driveshaft measures 22 3/4" from center of u-joint to center of u-joint at other end (as best as I can measure). I used a diagram from Arne to find measuring points (see below). I want to make sure that I have the correct driveshaft in my car. The reason I am concerned is that I am getting a large bang/clunk when hard accelerating in 1st gear, and it is possible the spline end could be hitting the tranny upon high torque (?), thus making the noise.

Any thoughts? Again, thanks Arne for your input!

My guess is the nose of the diff is rising upon acceleration. That causes driveshaft contact with the e-brake bracket or tunnel. It could also be that the bolts holding the rear of the diff to the mustache bar are loose and the diff is literally rotating causing contact somewhere. Check to obvious (loose bolts) and then head over to hybridz.org for additional solutions to mounting the diff positively.

Found a simnple solution (I believe) for my problem. There is no diff limiting strap over the front nose of the diff! When I had the 83 5 speed tranny and R200 diff installed, the diif strap was removed (probably because the 70 brackets did not work). Am ordering the later model diff strap bracket, strap, etc, from Nissan and this should resolve the problem. Will replace the diff mount insulator at the same time. Keep your fingers crossed!