Sorry guys - I'm going to punt this on eBay but I thought I'd mention it
here first. You at least might know what I'm talking about.

I have an Ensign Ranger II 6x9 folder adapted to use infra-red film.
It has a piece of Lee Filters no 87 IR filter fitted behind the lens.
This is optically-opaque and blocks anything shorter than 730nm.
I have been using it with Maco IR820c roll film, which has its
sensitivity peaking at, wait for it, 820nm.

The lens is an anastigmatic, 105mm f6.3. The shutter has three speeds:
1/25, 1/50 and 1/100. More to the point, it has a B and T setting.
Maco 820 works out at around 4 ISO in sunny conditions, so you stop down
and use the T setting. The lens stops down to f32, which helps.

Very basic flip-up viewfinder. Tripod sockets for landscape and portrait
orientation. Takes a cable release.

I have so far used it with the lens extended and the bellows wrapped in
cooking foil.

And before the conversion, it took cracking pics. Once you have seen a
sharp 6x9, the only next step is 4x5.

If anyone is interested, contact me off-list.