88 civic cluster swap

im wondering if the cluster from a 88-91 crx/civic will work in an 88 4dr civic. it has not only the no tach cluster...but the fucker doesnt have mph. only metric. haha. thats fun. its a friends car. i told her i could get her a us tach cluster from a junkyard car. hers is an auto. anything specific to lookout for? mech or electric speedo? sending units? ect. ive done them in yotas but not civics.