Posted for "George Braly" <gwbraly@gami.com>:

 Yes..
 
 There are several systems that have mechanical linkages with the throttle.
 
 But there are better electronic systems I the works, for that.
 
 Regards,  George
 
 
"""
  George,
     Thanks.  I think I understand.  If the rpm is relatively constant, and
  the power varied mainly by manifold pressure, then the wheel is working
 against the throttle backplate at low manifold pressure and realtively high
 crank rpm.
     Has anyone tried mechanically linking the throttle to a variable
  wastegate on the manifold between supercharger and carburetor?
     I was thinking that this way possibly the more-opened-up wastegate could
  let the pressure blow off when the throttle was pulled back, and increase
 the
 blow-off level as the throttle was opened.
  Terrence
"""