The normal JTR radiator installation for Chevy engines in a Z leaves plenty of room in the engine compartment. But I also have turbos in front of my engine and that's why I made this change.
I'm using a standard Arizona Z Car radiator for v8 Z's. However, this is a lot more work than what you may want to do. If you duplicate my system, you must seal off the standard upper inlet, lower the outlet to pass under the radiator support, weld on inlets for the radiator, remove the thermostat housing from the intake manifold, weld on bungs for the intake manifold coolant outlets,run coolant lines, and include a radiator fill location.
The good thing with this system is that the radiator filler is higher than the radiator.