I've done a 1G-GZE conversion in my RA23 and thank's to CLG's help and a little custom stuff, my radiator, which has to move further forward than on a GTE due to the GZE's SC crank pulley, now mounts on the outside of the radiator support panel. I used a KA/LB Laser radiator and had the filler neck and top pipe moved to suit.
This will take away the space you want to use to mount a I/C, but allows a 2 or 3 core radiator which is good to keep a GTE cool.
You may have to consider a long wide thin IC that sits below the radiator and mounts to the front chassis crossmember......