size cowl needed to clear typhoon intake...

As far as I know the typhoon is pretty much a photocopy of a performer rpm, which is the same height as a performer.. My performer fits under my stock hood no problem, with a 3/8" spacer.
 
without a spacer it will easily clear a 2.5" cowl hood.. i have a 1" spacer on mine and i still have plenty of room on my 2.5" cobra R hood.. it may even clear the stock hood with no spacer, but dont take my work for it on that