posted last week about upgrading to the yamaha 60 2 stroke and have done some research.talked to a good mechanic who dabbles in drag boats and he was not real familiar with yamaha.he said to be sure it had a rpm range of 5000-6000 because it had high gear ratio.he said some motors are designed to carry a load and more top end speed is hard to achieve.i looked on the yamaha website and the 70 is the same motor with 5000-6000 rpm range.the 60 is no longer made and there is no specs.my friend selling the motor says he ran 37 mph on his 1655dlx skiff.now i am thinking that i am only going to get a few more mph's than i get now(31-34) with my 40 johnson.i was hoping to at least get into the mid 40's with the 60.if anyone out there knows anything about this, let me know.i am undecided on what to do.