Torque Converter or Bad Trans

Hi, I have a 68 Valiant slant 6 with a904 and when i shift it into gear i have to give it a lot of gas for it to actually engage the gears and move. I think its a bad torque converter, but was hoping the amazing knowledge from this group would help me either confirm or know how to better figure out what is going on with it. Thanks for your help in advance.