GM to Mopar trans swap?!

About a year ago I snapped the output shaft in my 3 speed Manual 74 duster.(showing off of course) Just recently I've decided that I need to get the beast up and running again for summer cruise nights. My grandpa has an abandoned 84 5 speed manual Skyhawk that he said I can have the trans out of if I can get it to fit. Only condition is its my responsibility to dispose of the car afterward. From what I can find on the internet I can see that GM in the 80s did have a 4 bolt bell housing pattern but is it compatible with my 318? If not can I find a bell housing? I don't want to let a free 5 speed Slip through my hands any help is appreciated!