Z50 ATC70 motor conversion?


I have 4 or 5 incomplete ATC70 motors, I was wondering if I could take the cylinder head and the piston jug and piston from one of the ATC70 motors and install it on my Z50 thus increasing the displacement to 70cc instead of 50cc, I've heard it's possible but I would like to know what I need to do or what I need to make it happen.