GPM

I don't know, I wanted to run the belt drive, when I called Jesel they told me to change the belt every 60 hrs just to be safe. There's a lot of valve spring load with a solid roller. I can only imagine what will happen when the cam stops turning and the crank doesn't. It is all in what you are looking for, $800 for the belt drive, never know when it's going to break, $500 for a gear drive run it forever. To each his own.

mcollinstn

thickness is the issue.
A 3 pc cover has to have a ledge between the upper and lower cover to bolt to. chain runs too far out front to allow a ledge. if you run a crossover or space out your circ pump I can make you a 3 pc cover. (you'll also have to run a custom circ pump pulley...)

I don't advise to use gears. Harmonics are hard on steel cams.