slant 6 swap

Hi all
got some questions, I'm working on a 61 lancer that hasn't ran in at least 20 years.
So far I'm getting no ware with it just doesn't want to show any sign of life, I may wait till the weather warms before giving up on it and just swapping it out. The big question is what do I have to do to get the push button tranny to match up with a latter 225?
Thanks,
Larry