Even if the turbo vanes were locked open, it is a little bit too small for the 1FZ-FE. I know the name would suggest differently. Being that it is a 3782 and a 3582 is a pretty great fit, but
A 3582 has a max flow of about 76lbs of air
the 3782 has a max flow of about 55lbs of air even though it is a largish turbo, it runs a very small exhaust housing because it is used in Deisel applications and they do not rev very high, so it is choked out.
The turbo I have on my truck which is really about as small as I would go can flow about 64lbs of air but I an not running that much boost.
The problem with using a turbo that is too small for the engine is that you are overworking the turbo for moderate boost levels which in turn means a lot more heat, and much higher shaft speeds.
If you are only going to turn 10psi or so it would probably work pretty good. One of the other good things about the smaller turbo is that you are on the compresser map very early so you would be boosting almost instantly. But since you are always going to be in boost with any amount of load, much like a diesel you will need a well thought out charge cooling system.