Transmission question
 

I just have a simple question that I know I could get answered from the service department but I wanted to see what you guys had to say. I own an 89 5.0 automatic. I need to change the transmission fluid in it. What is the best type of transmission fluid to add and what is the best type of additive to help it. I know that there is Mercon/Dexron and Type-F. Which is best and what is the difference. Plus, how many quarts will i need if I drain the torque converter and the pan. Thanks a million.