They made the bell housing with that big open part on the bottom for a reason: making clutch changes easy. Before you had to remove the entire motor/transmission. Now you just drop the tranny (much easier than taking out a motor/tranny) take the cover off, remove the bottom bell housing cover, unbolt the clutch pressure plate, and resinstall.
My 42 Ford does not have this 'feature' so you have to take the motor/tranny out (although there are other methods... this is the book may).
My 43 GMC: drop the tranny (Clark 5 speed) a couple bolts/pins, replace the clutch pack, tranny back in place. Maybe 2 hours if you take your time.
