You shouldn’t have to grind completely thru the bellhousing to fit the S-10 clutch. But it definitely need relieving.Getrag240 5spd
I’ve had an S-10 clutch with a 4-speed, ZF 5-speed, and Getrag 240 and only the Getrag bellhousing needed to be relieved. In fact I was probably the first person to ever run that combo....Getrag with S-10 clutch. Back in 1992 or so.