If its a 1.1 and you put a 1.6 enigine in without changing the gearbox, you will run into problems. but if its a VTR you might just ge away with it
Gearbox Chage or not
1.1 to 1.6 CHANGE
1.4 to 1.6 CHANGE or Service More
1.6 8v to 1.6 16v Service atleast twice a year ( If you drive fast !)