IIRC, it's 28.. it's the wierd one in the family, not b/c it's a 4 speed, but b/c it's an 88.. we had this problem with my car... ended up using an 89 transaxle with a 89 clutch disk, and a 88 pressure plate... but yeah, if you want to verify, good place to look would be
www.rockauto.com that's where I get most of my info for replacing/ratting parts together.