Too big a cam might be the way to go on rebuild, now each bearing can be centered and cut true if block journals are off.

It amazes me with the machining tools available today any engine part needing precision isn’t with in .000x. Like buying a new $6000 block that needs line hone , deck, and other tune ups.
Doug

i agree with Doug.
as a former machinist, [45yrs worth, and still practicing !] the object is to make items to blueprint spec.
the newest and best machines out there [even five years ago] brag about how great they are at finishing items to the 0.0000 tolerance, and even self correct for tool wear as well as detecting tool breakage, stopping the machine when breakage is detected, or tool wear is at the limit of the tolerance.
my opinion is there is absolutely no reason reworking of items should be needed if bought from a reputable source with modern tooling.
mistakes can, and will happen, but there is just too much reworking needed anymore on a lot of different items, that should absolutely not be needed.
the only thing a guy should need to do is clean, inspect, and install. [unless you are like me, and try to save everything cast off by others, like abandoned dogs. i like dogs better, that's why i didn't say cats. ]
just a crabby old man mumbling in his oatmeal.
your mumbling will vary..............

I wouldn't tough the bearings in the block. measure the old cam that fit versus the new cam that won't. I bet you'll find the new cam has one or more journals that are too big.

When I hear myself saying it in my head, it’s seems pretty obvious....... to me at least.

You wouldn’t install a new crankshaft without measuring the journal sizes...... would you?
And if you didn’t...... well you could still plastigauge it.

Of course, plastigauge isn’t an option for a full round bearing..... so at a minimum you’d want to at least measure the journals and make sure they’re to size.

Same goes for straightness. I always check it...... on cranks and cams.

Factory BB Mopar blocks are fairly notorious for having screwed up cam tunnels........ so when a cam won’t go in, it’s 50/50 which is the culprit. If the cam is straight and to size..... the problem is the block.

In cases where one cam fits where another doesn’t....... its a safe bet the problem is the new cam.
But..... you gotta measure it to know for sure.

Probably the best analogy that could be be made - crank versus cam - measure them both.

Up until I stopped visiting the engine plants at Chrysler in the early 2001 time frame, we machined ALL the cam bearings after they were pressed in to the block.
They were called “green” bearings because they were unfinished.
We did this at the trans plant too on ALL the bushings in the auto transmissions.

Any updates yet? I have had to carve up a lot of cam bearings in the past to fit many camshafts
i have return maybe one instead of all of them. I do check the cams first for runout on the #2,3 and 4 cam bearing journals for run out to see if they are bent, if they are bent, they go back unless they're a steel roller cam
It is usually the block not machine to the proper I.D making the cam bearings to small

Once you understand this is how it was done at the factory, the poor fit and finish of the cam tunnel becomes somewhat of an “ah ha” moment.
At least, it was for me.

Measuring the cam bore sizing got moved way up near the top of the list of things to check for determining the viability of the block as a buildable core.
I had gotten screwed by that a couple times.
Block is all done and ready to assemble, and a cam bearing slips right through the bore.
At the time that happened, the repair to the block cost more than a core 440 block was worth.

Just a preliminary few measurements were taken at. The shop. The new cam is big. 3 of the 5 journals were 2 thousandths big. Compared to my old cam. They will polish the cam down to the same size as my original. Shoukd get it back in a few days.