I haven't done it with the Ford 460 since it has no cooling problem, but I did it with a 400 Oldsmobile that had difficulty staying cool in the summer. I plugged it's bypass and omitted the thermostat. That helped with the cooling noticeably. If you don't want to do the tap & plug route you can buy rubber caps (Dorman?) and use them with hose clamps.
Yeah, I guess - LoL. But it,s brand new again (I have the manifold off pretty regularly) and I'm gettin old and the old Mustang only does a hundred miles or so a year anyway, so it'll probably pop for the next owner!
Interesting idea though. Might do it just for fun. Lock-down is already getting really tedious.