And the winner is Drew and the AMA!
Drew's reponse;
(snip)
In regards to your question "...seat position cannot be above the rear tire" may I ask what rule you are referring to,
and where you found it.
The new (2007) AMA supplemental rulebook should be online within a week.
I believe that in regards to a special construction machine, the seat area (farthest to the rear) must not be above
the appex of the tire, or not above a line drawn vertically upward through the rear axle.
I hope this helps, and please write back if you have further questions.
My actual job for the BUB Motorcycle Speed Trials is measuring the engines, but I will try and help where I can.
Lastly, as I stated earlier, my plate is very full with my normal business so please understand when I say that
I'll get back with you as soon as possible.
(endsnip)
Whew! Back to bodywork,
Sam