Replacing 1.9 with 1.6
 

I have an opportunity to purchase a 1995 1.9 diesel Jetta with a blown engine.
I have a complete 1986 1.6 diesel Jetta that was in a wreck.
Talk is that the 1.6 will go into and replace the 1.9 in the 1995.
Is this so and what alterations are needed? Both are 5 speed standards.
Will the transmissions hook up and what about engine mounts and linkages?
Thanks for your help.