Swapping a 360 from A-Body/auto into a '78 Dodge Van with factory 318/4 speed - Advice?

Thanks guys, not sounding as simple as I was hoping! I don't have the flywheel from the 360, just the flex plate. Motor mounts are different too??? I suppose they are also different for a van as well...?
I was hoping to do this all in one weekend but it sounds like i might have to pull it out first and do some parts verifying/ordering afterwards.