Truth about roller cams.... BEFORE you make the switch......

Right! I but what does that have to do with a cam swap is what I'm asking. If im using a stock oil pump and swap to a roller cam why do I have to change the shaft and gear material? I dont understand how a cam change would effect the force on the gear and shaft
It doesn't, just depends of the material of the cam. It's not about additional force, but the wear of the different materials.