Flywheel ? for the /6 guys

I had 1965 through 1968 Dodge trucks, with the hydraulic clutch. I thought, whether it was small block V8 or slant six, the bellhousing, flywheel, and clutch were exactly the same. Maybe the flywheel was universal.
Clutch possibly. Bellhousing no, flywheel no. The bolt pattern on the bell to engine is different, and as stated the bolt holes in the flywheel are different. Also the center hole in the flywheel got larger between 67 and 68, on both the small block and slant six.
Also the bell, flywheel and clutch could be different on the slant (I don't know about the smallblock) depending on what trans was in the truck.