Hi I’m looking for some advice I’ve got a luego velocity with a 1.8 zetec silvertop with dellorto45,s Im thinking of putting a st170 in would this be a straight swop or would I have to start modifying Thanks

 

In short, NOT a direct swap. But it's not that hard.

One of the engine mounts is slightly different, exhaust side from memory.
Water pump is slightly smaller at 32mm and a slightly different angle depending on what silver top pump you have ( most probably fiesta / escort ).
Exhaust is bolt on but the st170 would benefit from a slightly larger bore. 2.5"
Inlet is bolt on but the st ports are higher. If there is enough metal you can port it to make it better.
Flywheel and clutch swap over.
Sumps can be swapped over but depending on what sump you have there may be a little work with the windage tray.
You will need a controller for the vvt or delete it, both have for's and against's. No body makes a stand alone unit any more and there was a lot of comments on them not being that reliable anyway. Stand alone with vvt won't be cheap.