you would be better with a straight swap tbh, lots of things needed to go 02a, pedal box, shifter etc. Its only necessary if you have lots more power tbh and even then you will lose the nice short ratios of the 020 so have to look into changing the final drive as well.
why are you changing? if you want a stronger box get someone to change the rivets holding the diff in with bolts, there is a kit available I believe.