difference between these 2 torque converters

[gotyorgoat]

Can anyone tell me the difference between these two torque converters? The blue one has a 6 stamped in the housing and GM 4M written on it. The black one has no markings.

Going into a 67 Lemans with a 455 and th400.

I know nothing about torque converters even after reading about them. Any suggestions?

[Skip Fix]

Hard to tell from the outside only way to tell what it wil do is install it or have someon cut them open and look at the components. Black one is smaller so will "probably" stall higher.

[gotyorgoat]

I took them to a shop that rebuilds only converters and they told me that it shouldn't hurt to run the smaller one becuase it looked custom and probably a higher stall. I guess I will give it a try since the blue one was in the trans that burned up and it seemed kind of sluggish before. Hard to get a difinitive answer on this issue so I guess I will just try it and see. Thanks for the input.

[Skip Fix]

If the blue one was on a tranny that was toast it would definitely need to be cut open to be sure there is no trash in it to ruin your new tranny.