New Engine For My 1.25

Hey guys

A couple of months ago I purchased a 1999 1.25 zetec ford fiesta.

Me and my dad done a lot of work to the car replacing a lot engine parts on it and put a bit of money into it as I wanted it to be a good runner as my first car.

Whilst doing a long drive my engine stared making a ticking noice and oil and smoke came out the car and after talking to a few mechanics i was told the engine was done and the best thing to do was to replace the whole engine block or scrap the car.

As we've put money into the car we don't want to scrap it.

We've been looking at engines online such as eBay and were struggling to find the exact same one.

My question is, if we were to buy a similar engine so another 1.25 zetec but off one of the later models how easy would it be to fit it? We have to tools to take the engine out and put the new one in but we don't want to spend the money on a engine for it not to fit in the car. Is it as easy as lifting the old one out dropping a new one in and connecting it all up and timing it or would it be challenge fitting the new one in with connections not being in the same place?

Any advise would be much appreciated.

Thanks in advance