75 280Z - 5 speed swap from 81 280ZX - any catches I should be aware of?

[cgsheen1]

Overdrive gear (final gear ratio) varied somewhat in the various years of the 5-speed... Difference shouldn't be huge, but...

[HusseinHolland]

6 hours ago, cgsheen1 said:

Overdrive gear (final gear ratio) varied somewhat in the various years of the 5-speed... Difference shouldn't be huge, but...

According to the chart here - 1981 has  .745 5th gear 

quite a range over the years as you pointed out, so if comparing to others, the year does matter