Then you have been really lucky they are as week as the 7 1/4 and not a good idea in a performance 4 speed situation. On all the 4 speed early a bodies I have had I have damaged all the ball and trunnions. Now I just automatically upgrade to the conversion set up regardless if auto or 4 speed. I have never been able to destroy one with a slant six yet- I hope I have not cursed myself-
