Sorry, I should pay better attention. I run a sintered iron disc with steel inserts on both the flywheel & pressure plate. I don't know what the reason would be for running bronze insert. I would think it would make a difference with the frictional coefficience. You can go to
http://umtrdragrace.com/ and check out the forum there. It's all stick car racing and there is more clutch and manual transmission info there than you will find anywhere else.