Glenn

Did this to my first MK2 RS2000 about 8yrs ago. Head will bolt straight to pinto block (doesn't have to be a 205 but use one if you can as they are a lot stronger).
Theres a few other parts to change as well - auxilary & crankshaft shaft pulley (as the timing belt is wider), re-routing of the heater pipes and a few other small bits I can't remember at the moment. If your fitting it to a standard bottom end then compression ratio will be a bit low. You could skim the head and/or block but check the valve/piston clearance as you may need to pocket the pistons to avoid contact. Stick on a pair of 45s and you've got an excellent conversion with plenty of power

Cheers
Neil