MK II Fiesta

I've got a mark II fiesta pop plus and was wondering whatsize engine i can put in whilst still taking advantageof the four speed ratio in know i can
put a 1300 making it a super sport but can i go higher
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.