Asking questions is all part of learning this stuff, the great thing is you are using proper grammar and asking clear questions.
A K50 out of anything in Australia wont work. They've got an integral bellhousing so you couldn't even swap one on if you tried.
Only an AE85 K50 might work, but don't even bother trying to find one, you'd find another T18 box easier.
Something you may like to look into though, TA22 celicas run a T50 box, its a 20 spline output as well. But I think they have a different extension housing and shifter location.
