Hypothethially speaking, if one was to put a HD galv chassis and do a cummins 6bt swap at the same time would you have to increase springs to a lifted kit to allow for the added weight to ride at a stock level? would a +2 Heavy load terrafirma ride at a level of a stock spring under that additional weight?? also has anyone completed a 6bt with auto transmission and kept the stock AWD nature with option hi/lo of the defender??

There's a few you tube videos on Cummins 4BT and 6BT swaps to Defenders and Series and even a Disovery They are mostly in the US as they can get a ready supply of Cummins. Interstingly they are falling out of fashion in the US, very very heavy, very large, quite smoky and power for capacity / weight is low. One of the main US guys fitting Cummins has stopped because there are better engines about now. He's looking at the Merc OM606, I like the Merc but its not good off road, no bottom end torque. I messaged him and suggested the Iveco engines, much lighter, easy to get parts and lots around. I run a Perkins in my Series and while mine is low power (63 hp) its smooth and I get 30+ mpg. I would also look at the later Perkins (not the 4256). The 6BT weight 1100 lbs (!!!!), that's horrendous and its not even a linered engine, even my 1960's Perkins is a dry liner so I could swap out liners and pistons for under £200 in situe, the Cummins has to go away for a rebore and hufting an 1100lb engine about is no joke. People talk about the Perkins 4203 as heavy - which it is, but its only 500lb

I've been looking lovingly at the 6bt conversion, theres one locally in a 110 & it taunts me when driven past

I have read all the fb stuff (loads) but forum posts are easier reference so heres one on LZ

https://www.landyzone.co.uk/land-rover/discovery-1-v8-cummins-6bt-conversion.324787/

as to springs...

https://www.landyzone.co.uk/land-rover/rear-springs-on-front-axle.364799/#post-4997464

Rich.

I know nothing about the engines to which you refer or the suggested application, but I picked up on the Cummins name.
When I was a truck driver, decades ago, they used to refer to the V8 version that Ford used in the D1000's as the 'self-destruct' engine, on account of it's high (for a diesel at that time) rpm & propensity to live up to it's name

norseman said:

I know nothing about the engines to which you refer or the suggested application, but I picked up on the Cummins name.
When I was a truck driver, decades ago, they used to refer to the V8 version that Ford used in the D1000's as the 'self-destruct' engine, on account of it's high (for a diesel at that time) rpm & propensity to live up to it's name

Click to expand...

All changed since then, the 6BT is the light truck worlds version of the 200tdi, very reliable, can be madly tuned.
Practically any vehicle you can think of will have been available with the 6bt
The ISB replaced it in approx 2000, again good lump, still a current engine but now up to nearly 7 litres capacity.

thanks for all the replies guys, I am currently a veterinary student in the UK (born in London) but live in Florida. Always wanted a defender and with the price of them state side, I saw it as an investment opportunity. Although, I dont want to get rid of it when I return back to the states in 2 years. I cant do any conversion prior to exporting it as it will be rejected at import inspections. So I picked up a 93' D110 CSW with a 200tdi that had sat for a year. Wasn't starting and the obvious rust on doors and rear cross member when I went to see it, so picked it up for £2100. Put a new battery in it and isolated a 12v supply to the stop solenoid and it started right up. Currently having fuel tank, lines, filter and lifter replaced while I return state side for Xmas to so my daughter. All repairs will be focused on rust in the vent area of bulk head, just ordered new door skins and rear cross member to spend my days doing during virtual classes. I am torn between an ls3 swap or a 6bt/LBZ Duramax swap when I return export it. I can start with suspension upgrades etc before its exported thus my questions regarding ride height. I dont plan to take it off road at all really, but want to keep the AWD. Dont mind changing to AUTO trans with the engines mentioned but really looking for advice for pros and cons for both and want upgrades to make prior to export. Chassis will be changed after export to so I can possibly do a HD one if needed.

Now that makes much more sense. You'll get an engine and parts much cheaper and you will, at least in the short term, avoid the big issue that's coming in the UK - the change of sentiment to be very anti-diesel, especially big ones that smoke once tuned - like the Cummins. I fully expect some quite punative road tax changes, a combination of the new "green revolution" plus paying for covid. I would certainly not be swapping out any engine for a diesel, especially a large one in the UK just now, but the US is different and I think you could get your investment back in a good few years use. What I would not be doing in teh US is buying a big new diesel truck, if Rivian and / or the Cybertruck take off there's going to be a lot of low mileage trucks on the market. Its not looking like we will get the Cybertruck in the UK, pity as it has to be THE school run vehile!