1973 Transplant Questions

Hi List:
After an ambitious freshening of what I thought was a desireable factory sunroof space Duster 318---It failed miserably on eBay--and I guess its not a valuable car.........so-since I like it and am stuck w/ it---I want to do a 440 transplant w/ buckets and console.
My inq is about the motor transplant. Has anyone done this on a 73 Duster?
What year 440 is best to buy?
I have a 727--is it enough or do I need to upgrade?
I am not a hot rodder or smoking tires / drag person.
Just want to make a Mist Green Duster that Plymouth never made but could have.
Thanks in advance, jeff
<img http://l-n.com/bourne/DUSTER/DSCN2194.JPG>