Sorry to drag this back up, but I thought I'd better put in some input.
The engine should fit easy. There are 351 Sigmas getting around, a 1UZ should fit especially with the recess. With that kind of power running through it, The Turbo Sigma diff might not handle it. I'd go for a narrowed 9 inch Ford Diff.
I run a turbo diff, it suits my conversion as the brakes are bigger than Commodore ones, so makes it easy for engineering.
What gearbox will you be running?
He has done a conversion already so I wont babble on about other things to consider.