Sorry for the resurrection of an old post!
But I just picked up a 72' 240z with the 2.3p swap in it.
And i gotta say, for stock set up this thing gets up!
As mentioned there's a large market for upgrades and interchangeable parts.
I bought the Z from my automotive teacher, who's been building hotrods/race cars for 20+ years.
He did the swap, and I gotta say did a pretty well job.
I can't speak for the swap difficulty, but I'll say the end result is impressive.
I'm looking forward to building on this, and seeing its potential.
Has anyone else done the swap?