'72 swap; R200 with 3.9 with T5

You might want to start reading up on the 71B if you decide to go that route. Nissan had three versions in the 280Z/280ZX. A so called "wide ratio" in the 280Z and two almost identical (5th is different) "close ratios" in the ZX. They also came in other models like the 720 truck series, which had three versions.

This thread is running atm and will give you a good starting point. http://www.classiczcars.com/forums/engine-drivetrain-s30/52177-gearbox-id.html

Chas