I'd say the biggest issue may be the front k-frame. I know for the 80's fwd mopars, moparts user dirt sells a conversion front sub-frame to drop in a SB and shows how to do the rest. exlinecustomauto.com

If the interepid front k-frame can fit a SB, the rest would just be fabbing your engine and trans mounts, adding a rear diff and trans/driveshaft tunnel mods if needed. May have to relocate gas tank. It would be a bunch of work but not cost all that much if you can do the fabbing yourself.