I have an old 727 tranny bolted to a small block Im thinking pre 72 but not sure. Im gonna change filter and have no idea what fluid to put in it. I was at parts store today and saw dexII / m there are so many dont know which one to use. The car is set up with a powerful 340 plan to race a little as well as criuse thanks for any help.

 

The cross branded DexII should work fine. There are many ways to reinstall the pan. Personally I like the newer hard reinforced rubber gasket used on the 518 trans