RB26 Motor Swap
 

I want to know if it is possible to swap the skyline RB26 Motor into a 1990 supra and if so, what would I need to change ,ecu, tranny, or what

Yes. Anything is possible with enough time and $$$. You would have to swap all that you mentioned, plus fabricate custom motor mounts, fabricate anything that did not fit in the engine bay right. Custom driveshaft would be needed. You might also have to cut into the firewall/transmission well to make it all fit. You would most likely have to cut into the body to get the right placement on the shifter. You would also need a very advanced understanding of fuel injection systems, and electrical wiring, as that engine is not designed to fit in a LHD car let alone in a Toyota.

In short this is not possible without some serious knowlege and resources.
Sorry, but its probably not possible for someone who has to ask this question.

dont forget the electronics, harnesses and all that will have to be replaced with ones from nissan, most of everything will have to be changed to accomodate the rb

I honestly dont think it would be a worth while swap, the 7m is already a great platform to work with. Have faith in your toyota! :D

it will be worthwile, but itll take a lot of work, like the 2jz they put in teh rx7 body, or the sr20 they put in the rx7 body, its not easy and it takes a lot of modification since they are different makes and obviously different motors, its not cheap either and it will take more patience than anything else, honestly, i would go with a platform that can be swapped in like a 1jz or a 2jz or just leave the 7m and build that up, its up to you personally and what you will be willing to deal with, many people start these projects and never finish cause they dont have the time, the money or the patience and it ends up being passed on from person to person