[Jac Mac]

You should not have any problems with the 300zx rear end, Ring gear is 230mm/9" dia & axles are tough, wheel stud pattern is same as ford ( 5 on 4.5" pcd) half shafts are one long/one short so you should be able to get it narrow enough for the cobra by using two of the short ones if necessary. Several running out here in OZ & NZ behind big Fords & Chevs.. Keep your eyes open for a Toyota Supra front end of 90's>> vintage, same stud pattern, as a donor for your front end. The S/H body is a good idea, a couple for sale privately in the site at moment IIRC, look at my gallery pics--- lots of work in a buck!!!