Anyone running a th400 in their a body?

I'm curious why one would want to go through all this hassle to put a TH400 behind their Mopar engine? I'm by no means a purist but short of a powerglide it would seem the 727 is a great 3 speed transmission. Just curious.
I have had both , why go to the trouble ? build the 727 right and forget it .
And yes , I have had a trans explosion ...