Alright, i just got home from popping a 1JZ w R154 into a GZ20 Soarer, and it fits quite well. The engine mounts all line up, and the gearbox mount lines up. The only problem is that the engine mounts are too "tall" or "thick" and so the mounts sit quite high up on the crossmember (like at the top).
Does anyone know of another mount which would drop this down, i would guess it would need to be 10-15mm shorter to sit properly in the cradle.