As an owner of two Plus 4's (1955 and 1968)
I'd advise the following.
I) Ditch the engine driven fan and go to a thermostatically controlled electric fan. My preference for a fan which pushes air through the rad.
2) Make sure the heat insulation blocks are fitted between carb and manifold.
3) A heat shield is a good idea between manifold and carb but then the risk is that the reflected heat will cook your starter motor.
4) Another tip but one which is not on topic is to relocate your ignition coil from the engine block to the inner wing to as heat cycles and engine vibration are not good for the windings
Arwyn
