I have a 76 Chevy Truck....... which doors fit?!?

[Canadian-Ron]

I have a 1976 Chevy truck but am wanting to buy some NEW doors for it, I'll be installing power windows & door locks out of a donor 81 Chevy truck, now I've heard there's a difference in these doors, what exactly is the difference?

Is it in how the door mounts to the cab? Body lines? Will the earlier doors not accept power accesories? Are the 81 accesories different in how they mount to the 76 door? Which doors should I be buying here guys?

Any help as always is appreciated, thanks in advance!