So I overfilled one of my reels with line by accident. Noticed there is a bit of extra resistance reeling in, and it doesn't cast as well. It doesn't look like the spooled line is touching anything, so why do these things happen?

casting or spinning?

How's a pausi trac rear end work in a Plymouth...

It just does.

if it's a casting reel, the line could be contacting the thumb bar or something. If it's a Plymouth, you're SOL.

Take some line off your overfilled spool and problem solved unless there are other issues not related.

This happened because your overfilled the spool. You said it not me.  Take your time next time re-filling your spool and avoid the element of operator error.

if it's a casting reel, the line could be contacting the thumb bar or something. If it's a Plymouth, you're SOL.

If it's a Plymouth and alive and kicking, you can bet it's kicking.