Maybe jumping ahead, but if you want to drift it, you'll prob need some sort of LSD or weld the diff. I have an '80ZX with a mild build L28, stock diff, Eibach lowering springs,KYB shocks and poly bushings. It won't drift(unless the roads are wet). Popular engine swaps if you can't have the L28 are Nissan RB motors and v8's. I cant imagine a v8 Z would make a great drift car with the added weight. Maybe an aluminum GM 350?
You can always replace the dish top pistons in your N42 motor with flat tops and replace the stock cam with a higher lift one. Mind you you'll likely have to replace the stock EFI with something like Megasquirt or Halltech or FAST EFI. Or go carbs. Pretty spendy.
I don't suppose your grandfather left you guys with a Toyota Soarer/Chaser?
The BMW E36 is a pretty good and plentiful drift car.