hi got a 2001 1.25 zetec with knackered engine, im trying to source a replacment but there seems to be two main 1.25 zetec engines, mine has the big front mounted airbox and four nuts to hold down rocker, am i stuck with trying to find that exact engine or can i replace with say a zetec s 1.25, i dont want to modify anything, just take one engine out and replace with another, any advice please, cheers.