4.70 or 3.53

Right, another question...

Land Rover Series are fitted with 4.70 ratio diffs, correct?

If I add 3.53 ratio diffs from a later defender, will this alter the gearing enough to make the engine struggle off road in low range, or will it still keep its poke in 1st and 2nd?

Taking in mind the engine is only a year old and goes like a rocket.

*2.3 Petrol.

Also, I dont do any towing at all, would 3.53 ratio diffs and an overdrive/high ratio transfer case be a bad mix for on the road?

I have the high ratio diffs in my swb with a 2.5 na deisel. I really like them, and the car goes really well. I have an overdrive and use it occasionally on the motorway and the beast will sit at 60 to 65 quite comfortably. I would go faster but I am too scared to try.
I dont do much off road so cant help there.
Remember its the ten spline diffs if you are buying them, there are loads around.

3.53 it is and it goes like a rocket.

Just gotta pick up the front diff now...