[Healeys] Air Intake Assembly Diameter

[Jack Feldman]

On the driver's side of my BT7 is a flexible tube that is supposed to being
air into the cockpit by ram action.

Can anyone of those privileged to use their cars year round tell me what the
inside diameter of the air intake assembly (on page R43 of the parts
manual)  that the tube is connected to?

There are a number of round 12V fans available from electronic surplus
houses and if I can find the right one I  want to try to improve the air
flow when stopped.

Thanks,

Jack