411 (Series 3-5) Exhaust Tailpipes

[Bellerophon]

Aero Dynes were designed for the rear window to be left open when
travelling in order that a through flow of air through the car be established, and
would allow the heating to work properly.
Tony Crook was always insistent that the rear window be left open as anyone
who rode with him would know.
One word of warning regarding the exhaust protruding beyond the rear bumper
on the V8's. It can be very costly if you reverse into anything as it is
very easy to break one of the exhaust manifolds, which are not easy to
replace.
My regards,
Bellerophon

[Kevin H]

See attached image which is an excerpt from a (Dennis) Sevier Lecture published in the Bristol Owners Club bulletin issue 41 (Summer '76)

[Rubbond]

As a child I flew regularly from Hurn airport to Cherbourg in a Bristol (3
cars and 12 passengers).
I'm sure however you couldn't open the windows!
The stories about their cars are getting weirder and weirder!
Andrew Knox.

[David Olivant]

I remember many years ago ownning a Hillman Imp with an openong rear
window. The handbook stated that under no circumstances was the car to be
driven with this window open, as exhaust fumes would be sucked into the
car.
Regards,
David

[Hydroglen]

The issue of fumes varies from car to car. It depends largely on the roof
line and design of the trunk (boot) and the angle of the exhaust pipe.
But why would Hillman go to the expense of fitting an opening window, and
then tell you not to open it? Maybe it was for necking couples, who having
parked in a secluded lay-by, wanted to avoid steaming up the windows!
Dorien

[David Olivant]

Necking couples! Have you ever been in a Hillman Imp?
David

[Hydroglen]

Seen one once....well it's the only reason I could think of, for a window
that can be used ONLY when parked!
Dorien