if i did put a 406 in my z would i have to change the tranny and any other components in the car?

 

No, a 406 is a 400 small block chevy that's been overbored. Your tranny and accessories would bolt up fine, although you might want to beef up the drive train a bit.

 

The external differences are the three frost plugs or if they only have two there is still a boss for one, that just isn't one there. Those are hard to see with the vehicle in the car though. The easy way to tell them apart is by the size and look of the weighted balancer.