Reworking my old 60 knocked out old rear pinion race. It was snug but came out. New one seemed to just drop in offly easy. I have heard this is not good?

3 choices,

Use green sleeve retainer Locktite.

or Use a rosebud torch and shrink the bore which will change the gear setup pattern a little

or strip the housing and send it to a machine shop and have a sleeve installed.

I'd do and have many times done the second choice.

So is housing JUNK!

Does the old race fit snug to go back in?
Does the old race have the same number as the new one?

It could be as simple as a parts error.

I wouldn't rule out that the bearing was manufactured on the low side of the specs. You might get another bearing race from a different source just to prevent another bearing from the same lot or production run. Beep