I am looking to fit a 4.6 Thor engine into a RR classic.
Does anyone know of a 6 speed auto that will fit, and/or has anyone done it that you know of?
Thanks

Not seem one done ... but that doesn't mean it cant be done though. RRPhil would be better to talk over the differences. I think the 6hp26 is quite a bit smaller than ZF4 speeds ... so you would need to be looking at both adapting the plate joins AND the lengths of shafts compared to existing known combinations.

To be honest, the effort I dont think would be worth it compared to just accepting you could fire in a new reconditioned box from the likes of ashcrofts for sub £1000

Also, dont Ashcrofts do a ZF control unit kit for the 4 speed, so you can specify the change points, lockups etc etc to suit your application. (Edit: Just checked, its called Compushift ) V8 or else ...

Thanks I will look up the compushift
If RRphil has any thoughts I would appreciate them.
N RR Classic 2 door Lincoln Green 1974 (restored at last), RR Classic 2 doors 1976 & 86 Blue and sand (restoring), 1995 200Tdi green, 1996 3.9 Vogue SE, RR TDV8 Westminster(day car).
Gone - 3x2 door classics V8's, 2 x P38, 2 x L322 TDV6's (Silver, Blue)

I wouldn't imagine it would be particularly driveable tbh.

The 4 speed is suited to the bhp/torque of the 4.6 whereas the 6 speed won't be. If you're towing with a 4 speed it's up and down the gears enough as it is without introducing an extra 2 gears.

I would imagine that it would never make it into 6th gear comfortable as there would never be enough torque to keep it there at the engine speed it would be doing.

I might however be totally wrong though!

David. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 5.0 SC Autobiography in Indus Silver with Jet/Ivory Interior
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

There isn't a simple six-speed solution because they're all electronically controlled. On the basis that you can buy a GM 4L80/Rover V8 adapter, the 6L80 should also work, but you'd need an aftermarket controller. Lot of effort (and you'd be much better off just sticking in a matching LS with it at the same time).

Re torque - there would be plenty, even with a much higher overdrive top - the additional gears are really only there to keep the engine within its most efficient RPM range for economy (see nine-speed Evoques etc.). There's no way a standard Classic with a ZF 4HP needs its V8 spinning at 3k RPM on the motorway!