Route 66 said:
Yep your right it is 1.7.
But it's easy to increase the ratio just by moving the fulcrum point but it destroys the rocking action at the tip.
It then becomes a sliding action which side loads the valve stem increasing the wear on the guide.
So to compensate for it they add a roller tip that eventully fails and becomes a valve keeper remover!
It's really hard to beat the stock design and most after market rockers actully weigh more then the stockers.
And if there was any real gains to be made by tieing the intake to the exhaust using the same shaft I would bet the General would have done it.
Look at the top engine builders and they all use the stockers unless the customer insist's otherwise. A&A Corvettes, ECS, etc.
Frankly if your doing your own work (I do) and don't want to break open the engine to replace the cam it's worth while if you get a good price on the rockers and springs and retainers (I did).
If you have to pay someone else to do it then it's a tolal waste of money IMHO :willy: