[MikeP]

We used to use misab plates between carb and manifold with spring washers on the outside of carb flanges on racing Imp engines (4 cylinder 10,000rpm) with no problems. They are not very thick when installed and with the spring washers amd cut carb vibration and fuel frothing but are solid enough to support the carbs without needing bracketry. Readily available from most motorsport outlets or Ebay.
Cheers
Mike