60's and 80's do not have the same converter bolt pattern. If you are using a 60 style flex plate you will have to specify that bolt pattern and have the pilot hub lengthened on the converter. I am also using a 60 plate (TCI SFI LS1 plate) and had my converter built to mate to it so that a pilot spacer was not needed.

 

Correct, they do not have the same pattern, and yes... you need to tell your TC manu what the TC will bolt to. As stated earlier PI does this for you. Not sure about other TC manu's... but companies capable of custom TC's can do just about anything for you... you just need to ask

Bill