imperialmotorcars,
thanks for the tips.
yes I am familiar with the areas you mention.

in my S type there is a removable mild steel under bumper "valance" where the red circle is.

yes, USA license plates are half the width of the one shown in your photos. In both the States I live or lived there is only 1 license plate used, at the bootlid ​​​​​​only.

yes I am familiar with the metal windscreen defroster/defogger part you mention, the S type has two on the front top of the dash cap. I believe all 1960's Jaguar models used the same part for the windscreen defroster / defogger. Two round hoses connect to them from the Heater box but otherwise their shape is identical to the attachment found in vacuum cleaners and used for upholstery fabric "combing" such as sofas and chairs, so I know exactly what you mean.

attached are two pictures showing the vacuum cleaner attachments which are identical in shape to the S type's defogger vents.








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I did this on the old Chrysler that I drove the wheels off once. Made an oval hole w/flange in the fresh air collector at the bottom of the windshield and connected it with a home-made flexible tube to the aft side of the air cleaner, in which I made a corresponding oval flange. It was an easy reach of only about 6 inches with nothing in the way.

The result was a Ram injection effect you mention, with cool air forced into the engine at road speed. Didn't do much at speeds lower than about 45mph though.

I wanted to do something like that to Nix but there's too much stuff in the way in the engine bay. Stuff like the distributor. We did make a Much bigger hole in the radiator mount and added a Chevy air cleaner w/flex tube, and that make quite a difference.

Maybe I'll be satisfied with that.

(';')

 

Diesel

The engines are so tough nd long lived. Son has a 95 Dodge 3/4 ton 4x4 . Power by the Cummins 12 valve in line 6. Over 400K and runs like a top.

 

Andy,
You might be right there, I have seen S3 cars bought in from Japan (Japanese delivered) that had no footwell vents - especially later cars towards 1985-86.
While I can't be sure, it is highly likely that you have the most important part necessary, which is the pressing behind the headlamp air intake (which is part of the front guard/fender) as I can't see any cost benefit to Jaguar in asking Pressed Steel, who stamped their panels, to delete it; though that is just a guess.
Checking would be an easy and quite quick job in two steps:
1. Do you have the mesh vents in the outboard headlamp chrome fillets (picture 1)? If the vents are there, you can almost guarantee the pressing will be too. But if you wish to be sure, continue to step 2. Even if you have solid fillets (like on USA spec cars I believe) with no mesh screens, it doesn't mean the pressing isn't there behind them and may I suggest removing the single screw holding it in and get your torch/flashlight ready...
2. Remove the chrome fillet from the headlamp and inspect behind at top of the headlamp and you should see essenially the inside of something in metal shaped like the inverse of Jose's vacuum cleaner attachment posted; located as in picture 2, by my terrible drawing. Much more comfortable with spanners than computers! I hope that is helpful to you. Thailand is such a beautiful country and I am delighted to think that there is at least one graceful Series 3 prowling its roads!

Outboard headlamps - 7 inch standard, 5 3/4 inch for USA. Note the mesh screens...

My attempt at showing where the round flexible plastic concertina ducting connects to the headlamp air intake.

 

the interior vents located at the kick panels were deleted in the Series 3 XJ cars but they kept the same headlamp escutcheons and hoses under the wing as in the Series 2 XJ.

The round vents inside the car are blocked off, and the pull open cables deleted. If you remove the vinyl covered kick panels you will see the vent holes blocked off.