What should internal temp be, of a beef meatloaf ?

There are 'rules' and there are individuals. you may find that you like your meatloaf done a little rarer-to 145 or 150 or 160, but the other direction, higher than 165, will get you overcooked dry, less flavorful meatloaf. When you touch your meatloaf/push down with your finger, it should be firm/ give slightly/spring back. If you stick a skewer in the center, the juices coming out should be barely pink or clear, not red/bloody (too raw.) If you ever undercooked your meatloaf, sliced into it and found it too raw inside, you could always return it to the oven.

All ground meats should be cooked to an internal temp of 165 degrees.