A good starting point would be a 27-10 Menz or one of the Menz knock offs in the same size. That's a true 27-10, BTW. A 28-10 Mejzlik would probably work well, but the Menz is a lot cheaper. I'm currently running a 28-10 Biela on a Brison 105 (104?), and have run the 27-10 Menz at about 6,200 rpm with a new motor. I haven't tached the Biela but it pulls to well to care.