It sounds like you have a 14 inch flywheel and a bellhousing for the 12 3/4 inch wheel. The 250 family inlines and the small block V8 can use the same flywheels, either size, and the same bellhousings as the back of both engines are exactly the same. FYI - the 14 inch wheel is commonly refered to as 168 teeth, the 12 3/4 as 153 teeth.
The bellhousing for the 12 3/4 inch wheel is straight down along the right side where the starter mounts. The bellhousing for the 14 inch wheels has a very noticible outward bulge for the starter nose. There is also a slight difference in the "taper" of the bellhousing from the block mount to the trans mount and that is where your interference is happening. You either need to swap the bellhousing or the flywheel. Knowing that the pressure plate fits what you have and the starter fits and meshes correctly to the flywheel it sounds like the bellhousing swap is the cure. This should be the only change you have to make as the clutch fork and tranny work with either housing. The dust shields for the bottom front of the bellhousings were made for both styles so that needs to be swapped also.
