Hi I'm a bit confused

since Garrett have a Twin Scroll houseing and the stock Evo 8-9 are already twin scroll. Is it possible just to make an adapter for the flange and do a direct swap
"lets say a 3071 Twin scroll Turbo"

tks

 

You could but that plate would be costly. You would then have to weld a flange on the stock manifold. A lot of work for a manifold that in my opinion won't flow enough top end for that turbo. Your spool will be nice. If you do the work yourself then it won't be that costly but if you aren't it would probably come out close on the expensive side.