Seein' as Eric is working his magic on the head, thought it's best to be reading up on a bit of tuning. Also got some really helpful insights from the blokes on The BritBike Forum. there is a rake of real, been there and done it experience on there.
So, anyway, I was looking at inlet tract calculations, and to get the benefit of the tuned length between 3,500 and 5,000 revs, the inlet needs to be 12 1/4" from the center of the inlet valve to the lip of the velocity stack.
As ya can see, it will make for an interesting oil tank!