That is pretty severe wear. I think you will find purchasing a used cheaper than the welding and machining. The 4.0 engine will run ok with the 4.6 ECU but will throw codes for lean fuel trims due to being calibrated for a 4.6 instead of a 4.0. It would do better with a 4.0 maf housing instead of the 4.6 housing. And of course it will throw SAI codes.

 

For what it’s worth, I did an LS Swap recently on my 04 Disco. Rover Engine is available and ran just fine before swap. 118k with secondary air. Head gasket and heads gone through 2019.

 

CA smog checks if SAI is present. I don't think you will get through smog without SAI.

You can also look for Range Rover P38 with a 4.6 engine. It's exactly the same engine like in a 2004 D2.

Or a whole 2003 Discovery for $1,800: https://orangecounty.craigslist.org/...686628345.html Part it out and rebuild the engine.

 

I am sure you can sell that for good money, might want to post it in the for sale section.

 

I may be interested in it. I sent you a DM.

 

Luckily for me, I live in a part of california that does not require smog checking unless selling the car. Will the engine run fine without SAI?

 

Yes, it will run fine without it.

 

Where is that? That might become a reason for me to move there. Here it's every two years and they inspect under the hood that you didn't modify anything of the emission system.

 

Siskiyou County. Some of the other nearby ones might not require it as well.

 

Or move a bit farther north, Washington State stopped emissions checks a few years ago. Reasoning was newer cars have made enough improvements that checking was not providing any benefits for the environment, and was a hassle for the citizens.