1.0 tanks have no return outlet, so assuming you are using the standard SR carb will need to swap your tank for one from any of the 1.2/1.3/1.4 carb models. Also you will need to fit a fuel return line (use the rubber braided stuff off ebay, its cheap) :)
As said the left-hand engine mount will need changing for any of the 1.2 upwards variety and the radiator and hoses are also different.
Most of the wiring is very similar but you will need to extend your oil pressure switch wire (blue wire) as the OHC engines have the switch at the bottom of the engine on the drivers side.
I'm sure the wiring for the coil is also already in the loom (thin black for live/thin green for earth back to clocks. (This green wire goes to behind the clocks and will have a spade fitting if its a Mk1 ready to connect to the SR type clocks).
Again the live feed to the carb will need to be taken off another wire as this is not on the 1.0 loom.
Hope this all helps
