I'm using the Yoshi road race cam, which is nearly identical to the 126-20 megacycle. My thinking was a little opposite of yours. I wanted more topend speed. My 79 cb650 had a 17in rear wheel all of the other models had a 16. I don't have my exact numbers in front of me, but I remember with a 18in rear and a 17/37 set up , a loss of 10% torque but a 10% higher top speed.