I had never had this trouble until recently with a 360 magnum.

I found the tight spot was next to the oil hole on each journal. I removed all the bearings. Then put a new set in the freezer overnight to shrink them down while cold. Then they pressed in very easily. After the acclimated to the block. The cam slid in just fine.

My assumption was when you beat the bearing in the cam bore with a press fit the bearing swells up. It also scrapes hard across the oil hole and scuffs bearing material pushing the bearing ID out of shape at the oil hole.

Leon