I wish i knew. On the insides it has helical gears and there is no difference between teeth. The teeth it is on now is no different than me turning it 180* or 90* or even 45*, everything looks the same on the inside and it seems like the only critical part is where the assembly bolts up on the cam sprocket and where the sprocket is on the cam. I emailed that guy and he asked if i had the other side as a reference (which i dont). I hope he could still do it. Also i got a response from arp and got quoted $1200-$1600 for main studs. I guess ill be using the stock ones.