As Bob pointed out, if it works, leave it alone. Clean it well, service and install the machine properly and use it. I looked over your thread on rebuilding this machine. It looks like a fine enough machine and you have done a nice job. That table is in way better shape than many are.
By far the cheapest and best fix is to just buy another machine. One that gives you a capability boost. If you have a working mill you are way ahead of many folks. You can bide your time and when a better machine shows up, you will know what a good deal looks Iike. For example, you have a round column machi e, does it stay registered? Does that head have a low gear, or is it just belts? How about variable speed? Whatever the issues, use the machine as is - down the road, buy another one which is better. You existing machine, if it is clean and running well will sell on just fine.