Did you try installing the cam after each new bearing was installed ? If not that is worth doing in the future.
I wouldn't even think of trying to install any cam bearing in the motor with the crank and rods in it in the car, I'm thinking you are doing that Good luck, you will get it done, keep after it
Maybe see if you can come up with a old cam and use it to fit the bearings in so your cam will slide in decently, you can take a hacksaw and put groove in the cam journals by sawing them all the way across them in a little bit deeper than the cam O.D.
I've never done that so hopefully someone else that has will chime in with a picture or better instructions on doing that
I have and use a bearing knife to fit (scrape them) my bad bearings a little bit at a time, one bearing at a time also
I've never had to fit a cam bearing in a Chevy or Ford block I don't do many of them either, probably around a hundred Mopars to each one of the other brands
Not all Mopars need the bearings fitted, some do and I hate them