Larry,
Do you know what your actual power output is?  I assume you're not stock
given all that racing.
 
I am also a big advocate of RTV.  It makes a difference.
 
3.5 inches is probably near the lower practical limit on inlet size for
a 360.  The mass flow to achieve comfortable (340-380 degF) full
throttle cruise CHTs brings the inlet velocity ratio up pretty high
(~1.0), relying solely on internal pressure recovery i.e. good
diffusers.  
Chris  
 
 
 
Chris Zavatson
N91CZ
360std
www.N91CZ.com