I have found the Super Tigres respond well to porting. I had a tired old Italian S .40 and after porting and a new ring it turned a 10X6 MA on 5% at 15,000 rpm with the first version of the swing muffler. I made an adapter to use the .60 size swing muffler on it and it turned 15,400 rpm. The Super Tigres are one of my favorites. I have also gotten great results porting the ST S .61.s as well.

Regards, Bill