On Ice, I have only sold a few of the 3550 gaskets. And I've never gotten a hold of a TKO 500/600 shifter so I don't have a template. However, I went over to Steeda's website and compared the pictures of the TR3550/TKO and the 500/600 and the bases are definitely different. So the gasket set I have for the 3550 won't work with a 500/600. If I ever get a hold of a 500/600 shifter (aftermarket or stock) I can design a template. Sorry!