If you want a cheap running a12, check the papers and make a road trip down to perth on the weekend to pick one up. You could freight oe, buts its probably to expensive for that.

I would first get your mechanic friend to check excatly what the problem is. It might be cheaper and eaiser to just replace the worn parts.

Its unlikly that the bottom end is cactus for example, so you dont actually have to pull the entire engine.

Datsun parts arnt that expensive. Hec thats half the reason most of us are involved in them.