If your 1.0 doesn't have the ecc stuff on it (which it probably wont have) it's a pretty direct swap.
If the 1.2 came off a facelift model with the ecc stuff in it you can use the complete inlet stuff from the 1.0. You can swap the manifold complete with carb etc. As far as my experiences go it's usually the most easy to do this (inlet manifold, complete with carb, airpan etc). And then all the fittings will be exactly the same and the car will run just fine. That is if the 1.0 also ran fine
You might need some new manifold gaskets if you do this btw.
There could also be a metal pipe which comes from the exhaust manifold (on the 1.2) which goes to the inlet. When using the 1.0 stuff I don't think that will fit on there so you can just block that pipe off.
Did around 5 swaps this way and they all still work
However if you are also changing the ignition stuff (e.g. electronic ignition from the 1.2 car) don't forget to change the coil as well, that is needed afaik. But I don't know if you also thinking of swapping that.
Oh yeah, don't know how many miles that 1.2 did. But it could be a nice idea to change the cambelt too when it's out of the car. Most of the work like that on the engine is much easier when it's out of the car than in!
Same goes with changing the inlet manifold and stuff obviously
As for the gearbox, that is also a direct fit and the 5 will work right away. You don't need to change anything on the car itself to make that work. You might want to get yourself a gearknob off a 5 speed car to make it look nicer, otherwise you have a secret and hidden 5!
That's about some stuff that comes up right now, but since I'm tired the brain refuses to remember things clearly
. As Speedle said, if you run into any problems post em and we can answer them quite fast!
