I wound up after a lot of experimentation with my '68 GTX (there's a thread on here of mine
somewhere) of going whole hog - bought a Griffin "Exact Fit" aluminum radiator ($$$) and
utilizing a new factory shroud for 26" radiators, along with a direct drive 7-blade fan like
others have said.
I could not use any viscous coupling type fans because there was not enough room - the
Griffin is FAT. Even the "Jaguar" shorty fan clutch wouldn't work...
Wound up direct drive with the big fan (bought from Summit) and a 1.5" spacer, which got
the fan blades half in/half out of the shroud.
It works quite well overall, although I'd still like some auxiliary cooling for stop/go situations...
The only thing I haven't done is try the Flowkooler water pump:
https://flowkoolerwaterpumps.com/co...rysler-dodge-plymouth-hemi-hi-flow-water-pump
That's definitely on the future WANT list, though. It will happen eventually.