Help can someone tell me if the 72 z's came with a 4 spd or a 5 spd transmission.if they come with a 4 spd can you put a 5 spd in it without changing the motor?

Choices were a 4 speed manual, or a 3 speed automatic. No factory 5 speed option in North America until 1977.

Swapping in a 5 speed is common. Use the search feature here and you'll find lots of data on it.